History of PKU - Origins
Pearl S. Buck
Shawn E. Christ and Stanley Finger
Psychology Department, Washington University, St. Louis, MO 63130-4899 USA
Blau, N. (2006) PKU and BH4: Advances in Phenylketonuria and Tetrahydrobiopterin. Heilbronn, SPS Verlagsgesellschaft
Pearl S.Buck and Phenylketonuria
I would gladly have written nothing if I could have just an average child in Carol. Average children seem such a wonderful joy to me – I wouldn't ask for a clever, bright child if I could have had her just average.
(Pearl S. Buck, a letter to Polly Small )
Having authored over 70 books in her career, Pearl S. Buck (1892-1973) is well remembered for her contributions to world literature. Her most highly regarded book, The Good Earth, a story detailing the exploits of a Chinese peasant farmer, was published in 1931  and was awarded the Pulitzer Prize the following year.. As a result of this book and her other “rich and genuine epic portrayals of Chinese peasant life, and for masterpieces of biography," Pearl Buck later became the first American woman to win the Nobel Prize for literature. This was in 1938. Even now, The Good Earth continues to be regarded as a classic of American, and really world, literature.
Nevertheless, it would be in a much later and briefer work that Buck would draw attention to the difficulties she personally had to face with a child from her first marriage --- a daughter who was profoundly retarded. In May 1950, The Child Who Never Grew first appeared in “The Lady’s Home Journal” . The piece about a perfectionist mother struggling to accept an imperfect child caused such a sensation that it was republished in book format that September .
The present chapter deals with this mentally handicapped child, Buck’s landmark in literature about the retarded, her later discovery that her daughter had phenylketonuria (PKU), and how a talented writer’s personal experiences ultimately changed many lives.[i]
The Hidden Child
Prior to the release of The Child Who Never Grew, Buck spent almost two decades trying to conceal her daughter Carol from the world. The girl’s existence was circumvented in interviews, and friends were begged never to mention her to the press or, for that matter, to anyone else. Obviously pained by her child’s mental status, the most the world-famous author would reveal in interviews was that she had "two little daughters. One is away at school and one . . . is at home with us" (Pearl S. Buck ).
In a letter to one of her closest friends, Buck once confided:
It is not a shame at all but something private and sacred, as sorrow must be. I am sore to the touch there and I cannot endure even the touch of sympathy. Silence is best and far the easiest for me. I suppose this is because I am not resigned and never can be. I endure it because I must, but I am not resigned. So make no mention of her and so spare me. (Pearl S. Buck, letter to Emma Edmunds White )
In coming forward to share Carol’s condition, Buck made a painful personal as well as a bold professional decision. "I have been a long time making up my mind to write this story," was the opening sentence of The Child Who Never Grew. No longer would she continue to be secretive about Carol. Instead, she would devote herself to telling the retarded child’s story and trying to help her and others like her.
Caroline Grace Buck was born to (John) Lossing Buck and Pearl Sydenstricker Buck in 1920. Weighing seven pounds, eight ounces, she appeared to be healthy. Neither parent suspected that she was destined to experience severe mental retardation due to an inability to metabolize the amino acid phenylalanine. In fact, PKU was not even a recognized disease entity at the time.
Carol’s early infancy in China yielded few hints of her future difficulties. In fact, she seemed to have a wise demeanor. Quoting Buck:
I remember I said to the nurse, “Doesn’t she look very wise for her age?” She was less than an hour old. . .. . I remember when she was [three months old] that she lay in her little basket upon the sun deck of a ship. I had taken her there for the morning air as we traveled. The people who promenaded upon the deck stopped often to look at her, and my pride grew as they spoke of her unusual beauty and of the intelligence of her deep blue eyes. 
As Carol approached her third birthday, however, it became increasingly apparent that she was delayed in her motor and cognitive development. Unlike her peers, her movements were poorly coordinated, and she had not yet started to speak. Buck found needed comfort in stories from friends about babies that thrived, even though they were slow to walk and talk.
By age four, Carol’s mother was panic-stricken. "The hour of awakening to sad truth" hit hard, she wrote. At the time, a visiting American psychologist was lecturing on child development. It was after listening to him that Buck realized just how far behind other children Carol had fallen. Afterward, she spoke with the lecturer, who
pointed out to me the danger signs I had not seen, or would not see. The child's span of attention was very short indeed, far shorter than it should have been at her age. Much of her fleet light running had no purpose — it was merely motion. Her eyes, so pure in their blue, were blank when one gazed into their depths. They did not hold or respond. They were changeless. Something was very wrong. 
Other doctors were now consulted and the consensus was that Carol should be taken from China to the United States for further testing and evaluation. Buck followed the recommendation and sailed back to the States, where she took Carol to child clinics, endocrinologists, and psychologists. The consultation of greatest significance took place at the Mayo Clinic in Rochester, Minnesota. After a thorough examination, she was told that, for some unknown reason, her child's mind had definitely stopped growing --- she was and would remain hopelessly retarded. To think otherwise would be deceiving herself.
A compassionate doctor with a strong German accent further advised the distraught young mother to "find a place where [Carol] can be happy and leave her there and live your own life" . Buck would later write:
I don't know of any blow in all my life that was as rending. It was as if my very flesh were torn. It was beyond belief, and yet I knew I had to believe it, and shape my life around the fact. (Pearl S. Buck )
Finding no acceptable alternative, especially after returning to China, Buck decided to find a good care-taking institution in America for her daughter. But before relinquishing Carol’s day-to-day care to someone else, she decided to do a few things of her own. She now spent her time trying to teach Carol to read and write, to distinguish colors and musical notes, and to sing some songs. In a sense, she wanted to know whether Carol was capable of any learning, perhaps to comfort herself, before institutionalizing her. Some of this parental evaluation took place in Nanking, some in Japan, and some in Shanghai, as civil wars and xenophobia were now making some parts of China extremely dangerous for foreigners.
Buck discovered that her daughter could indeed be taught some things. She learned to write her name, sing simple songs, and read very simple sentences, albeit with concerted effort. But progress was torturously slow and frustrating, both for mother and child. Turning to the fundamental issue of whether Carol was capable of understanding what she was doing or just proceeding mechanically, Buck would later write:
I happened to take her little right hand to guide it in writing a word. It was wet with perspiration. I took both her hands and opened them and saw they were wet. I realized then that the child was under intense strain, that she was trying her very best for my sake, submitting to something she did not in the least understand, with an angelic wish to please me. She was not really learning anything.
.. . . She might after much effort be able to read a little, but she could never enjoy books. She might learn to write her name, but she would never find in writing a means of communication. Music she could hear with joy, but she could never make it. 
In 1929, a few months after Carol’s ninth birthday, Buck traveled with Carol and her younger sister Janice, who had been adopted four years earlier, back to the United States.[ii] After an extensive search of American institutions, she selected the Training School at Vineland for Carol. It was located in southern New Jersey, not far from Trenton and Philadelphia.
Buck later explained that Vineland was chosen because of the kindness shown to its residents. In addition, it had a stellar history as a training school, especially with birth-injured children (e.g., those with cerebral palsy). Moreover, it was a cutting edge research institution --- the first in the United States to use the Binet Test for measuring intellect and the site where the Social Maturity Scale had been devised.
It was with this knowledge about Vineland, and with some words about the pain involved in placing one’s child in someone else's care, that Buck's short narrative, The Child Who Never Grew, ends. Buck returned to China accompanied only by Janice after leaving Vineland and making a quick trip to New York to meet with her publisher.
A Mother’s Remorse and a Retarded Child’s Life
Buck did not see Carol again for three years, feeling guilty but also confessing in private that, at times, she wished her daughter would just die. In a published interview, however, it is only her maternal guilt that is revealed:
I left her all alone for three years and that, I know now, was wrong for me to have done. It was wrong for her and for me. After all, she had never been separated from me before and for it to be so sudden and so complete was hard on us both. True I paid a woman friend to go and see her, and she reported to me each month, but it was not the same as visiting her myself. I vowed I would go back and see her at least once a year. (Pearl S. Buck )
Buck did, in fact, move from China to a renovated farmhouse in Perkasie, Pennsylvania, not terribly far from Vineland, New Jersey. Lossing Buck, however, did not accompany her back to America. After years of an unhappy marriage, she divorced him in 1935 and married her editor, Richard Walsh. As seen by Pearl S. Buck, Lossing had withdrawn from her and Carol well before the divorce, effectively making her a single parent.[iii]
We learn that Carol was occasionally taken out of Vineland to visit her mother in Perkasie from Buck's Treasure Book, which was her collected but unpublished notes about her interactions with her children. A recurrent theme in the Treasure Book is Buck’s own struggle to not let herself get too engrossed with any of her children. After being tied down by Carol for so long, she wanted to have her own life and her freedom.
The following passage about Carol, who was then twenty, dates from 1940:
This is a beautiful day. Carol is at home --- I like to have her here but all sense of flesh, my flesh, is gone. I feel toward her as tenderly as ever, but I am no longer torn. I am, I suppose, what may be called "resigned" at last. Agony has become static --- it is true but I will not disturb it or allow it to move in me. (Pearl S. Buck )
More is learned about Buck's interactions with her retarded daughter and Carol's life and development at Vineland from the second edition of The Child Who Never Grew. Unlike the original edition, it contains a sixteen-page "Afterward," written by Janice Walsh, Buck’s adopted second child. In addition to becoming Carol’s legal guardian in 1973, Janice became an active member of the Board of Directors of the Training School at Vineland, and also served as President of the Pearl S. Buck Foundation. Moreover, she had trained as an occupational therapist specializing in working with the mentally retarded.
Janice’s section describes how she and her mother eventually came to realize that Carol had PKU:
On one of my brief visits home, sometime in the 1960s, Mother told me that she had learned the reason for Carol's mental retardation. Carol had an unusual disease called PKU (phenylketonuria). This condition resulted from an inability to metabolize phenylalanine, an essential amino acid. In addition to causing mental retardation, PKU was associated with blond hair, blue eyes, eczema of the skin, and an overpowering musty odor, which was perhaps due to the inability to absorb or process protein. (Carol had all of these attributes.) Mother explained that the condition was inherited, and must have been present in both her genes and Lossing's genes. When we learned about PKU, a method of diagnosing the condition by testing urine samples from the diaper had recently been developed. 
PKU had been discovered by Norwegian physician and biochemist Asbjørn Følling more than 20 years earlier . In 1934, Følling was approached by a mother who was searching for an explanation for the apparent failure of her two children to development mentally. Having discovered that the children’s urine contained higher-than-normal levels of phenylpyruvic acid, Følling went on to identify a number of other individuals who all shared two key traits — all were mentally retarded and all secreted high levels of phenylpyruvic acid in their urine. Følling later concluded (correctly) that the condition was hereditary and that increased levels of phenylpyrouvic acid in the urine reflected an inability to metabolize phenylalanine, a common amino acid.
Despite all of this, it was not until the 1950s that advances in newborn screening and dietary intervention coupled with increased interest in mental health policy, motivated medical professionals to begin testing patients in existing institutions for evidence of PKU. The discovery of Carol’s PKU was undoubtedly a result of this growing movement. Unfortunately, Carol was in her 30s at the time, which was well past the age where a change her diet could have helped her to develop normally.
Although Pearl Buck learned that Carol’s mental state could not be reversed, having a biomedical explanation for Carol's condition seems to have had two effects on the world-famous author and social activist. On the one hand, she finally had an answer to the question "why?" She must have been relieved to learn that her daughter’s condition had nothing to do with poor mothering. But on the other hand, she now knew that her own genes did in fact contribute to Carol's severe mental disability.
Janice further informs the reader that her mother, who died from lung cancer at age 80 in 1973, saw Carol for the last time in 1972. Rather than having Carol taken to her home, she visited her at Vineland. Janice acknowledges that her mother was less than an ideal mother to her children. And Pearl S. Buck probably would have agreed. Perhaps because of her failures with Carol, and her own need for intellectual stimulation and perfection, she once said that she valued the relationship between man and woman more than that between mother and child. She even added: "I enjoyed my children, and still enjoy them as human beings and as individuals, but not because I'm a ‘mother’" (Pearl S. Buck ).
Pearl S. Buck tended to think of herself not as a mother but as an understanding woman with responsibilities. Consistent with this image, she served as a major fundraiser for Vineland and had become an activist spokesperson for its residents. She not only contributed money to build a new two-story dormitory with a porch and wading pool for Carol and fifteen other girls, but also assigned the royalties from the first edition of The Child Who Never Grew to the school.
But Did Carol Grow?
In her "Afterward," Janice Walsh makes the point that the child who never grew did in fact show some growth after she had been left at Vineland. To quote:
She never learned to read or write, but she did learn to color, write her name, and verbalize her needs. She also learned to sew simple projects and to master many self-care skills that enhanced her independence. She learned to bathe and dress herself with some supervision, to tie her shoelaces, to be independent in toileting and tooth brushing, and to comb and brush her hair with verbal reminders. She also became skilled at using a fork and spoon . . .. 
Additionally, Carol continued to develop her skills in music. She learned to play her phonograph and use her radios (though they often dropped and broke). She would also hum along to the music. When it came to sports, her abilities were fairly good for someone severely afflicted with PKU. She could roller skate, shoot baskets, and run in Special Olympics events. She also had a tricycle, which she would continue to ride around Vineland into her seventies.
Nevertheless, Carol did not do well in vocational training, which included attending a supervised workshop at Vineland while she was in her fifties. Her three biggest problems were her short attention span and inability to focus on her work, the fact that she quickly became frustrated when parts did not fit together easily, and her need for constant and intensive guidance. Without question, she displayed profound learning and attentional disabilities.
With regard to speech and language, even as an adult, Janice tells us that
Carol's speech was not clear, and since I did not see her daily, I often found it difficult to understand her sentences. But when she spoke in clear, single words, I could usually understand what she was trying to express. She seemed to understand me quite well, but I had to keep the communication simple. 
In 1991, Carol Buck, like her mother two decades earlier, was diagnosed with lung cancer. She underwent several operations and was given chemotherapy. Nevertheless, she succumbed to the disease, dying in her sleep on September 30, 1992. “The child who never grew” was buried at Vineland, which had been the only home she had known since her early childhood --- her home for more than sixty years.
Retardation in Buck’s Writings
According to Buck, because her husband thought that sending their retarded daughter to an expensive, private institution was a waste of money, she was compelled to meet all the expenses herself. The alternative, which she was never prepared to accept, was to turn Carol over to some free but depressing state institution. In his authorized biography of Pearl S. Buck, Theodore F. Harris wrote: “She was alone in her care for the child. It became entirely her responsibility to provide for the child's future” .
Desperate to secure the necessary funds, Buck approached the Presbyterian Mission Board in New York. Mrs. John H. Finley, a member of the Board and the wife of a New York Times executive, was so “moved by the story of a brave young mother trying to care for a retarded child alone" that she provided a $2,000 loan . In addition, the Board agreed to pay $500, if the struggling young mother would write a children’s story about missionaries . These backers gave Buck the time and freedom she needed to attempt to make a success of herself as a writer. Soon Pearl S. Buck would be a household name, and she would be able to provide more financial support that would be required for Carol.
Janice wrote that Carol "was one of the primary impetuses that spurred my mother to write" . Peter Conn, one of the Buck biographers, added:
Whatever other motives compelled Buck to sit down at her typewriter every time she could reserve ten minutes or a quarter-hour from household chores, her fears about Carol [not being properly cared for] were the most urgent. It goes only a little too far to say that Pearl S. Buck's entire career as a writer was anchored in her anxiety for her child. 
Buck herself had this to say:
.. . . I was in the United States with my retarded child, for whose care and future I was solely responsible. For her sake I needed money, for I knew all too well the cost of lifelong care for such a child. . . . I was well paid as teachers go, but now I had to earn much more. A Christian organization said to me: 'If you will write a book for children with a Christian ending, we will give you five hundred dollars."
Thus I contracted for The Young Revolutionist. I returned to China then and first wrote The Good Earth because it was in my mind, waiting. Then, reluctantly, I fulfilled my contract for The Young Revolutionist. 
The Good Earth remained on the bestseller list for almost two years, helped in part by the publicity surrounding the 1932 Pulitzer Prize that it received. Grossing over $1,000,000 (Buck hoped it would make $20,000), its proceeds allowed the author to settle debts and establish a substantial (for the time) $40,000 endowment at Vineland for her retarded daughter.
Carol’s plight also influenced Buck’s literature directly. In The Good Earth, which is about a Chinese peasant who amasses a fortune by accumulating land and skillfully farming it, we read that the protagonist, Wang Lung, and his dutiful wife, O-lan, had a retarded baby girl. The child, who is never referred to by name, was a source of great sorrow and heart-felt pain to her compassionate father.
Wang Lung had, therefore, at this time no sorrow of any kind, unless it was this sorrow, that his eldest girl child neither spoke nor did those things which were right for her age, but only smiled her baby smile still when she caught her father's glance. Whether it was the desperate first year of her life or the starving or what it was, month after month went past and Wang Lung waited for the first words to come from her lips, even for his name which the children called him, "da-da." But no sound came, only the sweet, empty smile, and when he looked at her he groaned forth, "Little fool --- my poor little fool ---". And in his heart he cried to himself, "If I had sold this poor mouse, and they found her thus they would have killed her." 
Wang Lung's daughter's retardation was so profound that family members had to feed her. They also had to take her outside to feel the warm rays of the sun and then back into the house at night or when it began to rain. The girl would laugh when others would cry, and would spend hours at a time folding or twisting a small piece of cloth, without any real comprehension of what she was doing. "She saw no one who came and went and knew no face except her father's and her mother's" . In his later years, the kindly Wang Lung would be angered by his snobbish daughter-in-law, who would "not suffer the poor fool near her" and dared to remark: "Such a one should not be alive at all" .
Peter Conn, in his cultural biography of Pearl S. Buck, would write: "The nameless child, who serves throughout the novel as a symbol of humanity's essential helplessness, is Pearl's anguished, barely disguised memorial to Carol" .. At the time, Carol was still hidden from the public eye. Indeed, Buck did not mention Carol by name or reveal her mental deficiencies in any of her early writings, including her more autobiographical pieces. But this changed after she published The Child Who Never Grew in 1950. Four years later, she revealed some of the suffering she experienced as the mother of a retarded child in My Several Worlds .. But even more noteworthy is The Gifts They Bring . In this 1965 book, written with Gweneth Zarfoss, people with mental retardation are presented in a very positive light. No longer pitiful, embarrassments, or burdens to society, the mentally handicapped are portrayed as "beautiful minds" and overlooked contributors to the diverse world in which we live.
Passages about having a retarded child can also be found in The Time is Noon, one of Buck's more revealing autobiographical novels. This deeply personal and even "confessional" work was published in 1967, although most of it was written in the 1930s. By the time of its publication, the Western public was much more accepting of the mentally handicapped and knowledgeable about children and young adults with PKU. The heroine, Joan Richards is the daughter of a demanding, narrow-minded priest. After Joan gives birth to a retarded son, her personality and outlook on life changes. At one point in the autobiography-novel, Buck shares the moment in which Joan is first told that her child is destined to a life of mental retardation. In drafting this very intimate passage, Buck very clear drew from her own experiences with Carol:
“Dr. Crabbe, where is his mind?”
The pain of waiting for birth was nothing to the pain of this waiting. All of life, all the world, stopped, faded, was nothing. In all the world there was nothing but this tiny room, this old man, this child, herself. But he did not answer for a long time. At last he began to put on the garments again, slowly, carefully, to fasten them expertly, securely. At last when the child was dressed, he looked at Joan, his face a twist of wrinkles.
"His mind was never born, Joan—my dear child—" 
Later in the novel, a woman gives Joan advice that is more than vaguely reminiscent of what the author heard decades earlier:
“You can’t ever put him away anywhere,” said Mrs. Mark. “That’s what folks don’t understand. Putting his body away wouldn’t help. You can’t put your child away from your heart. Besides, you don’t want to miss everything of him just because you haven’t all of him. He’s got his own ways. He’s Paul. Don’t measure him by other people. Just take him as he is. If he talks, those few words he’ll say will mean more to you than anybody’s.” 
An Advocate for the Mentally Retarded
Pearl S. Buck, who for years kept Carol’s condition a secret from all but a few close friends, not only broke new ground by telling her story in The Child Who Never Grew, but became an advocate for mentally retarded children. She served as an active member of the Board of Directors at the Vineland Training School and, in a more visible capacity, chaired the Governor's Committee for the Mentally Retarded in the State of Pennsylvania. Her efforts had a stimulating effect on other people who were well known at the time. She helped them accept and tell others about their retarded children and siblings, and this, in turn, proved instrumental in making people aware of the mentally handicapped and their special needs. It would not be an exaggeration to say that some of the foundations that were set up after 1950, and considerable legislation that was passed, was stimulated at least in part by her name recognition and well-publicized campaigns.
Eunice Kennedy Shriver, sister of President John Fitzgerald Kennedy, was one of the individuals influenced by Buck. She wrote about her retarded sister Rosemary, the need to help retarded people become useful citizens, and the Joseph P. Kennedy Jr. Foundation for the mentally retarded, in the “Saturday Evening Post” in 1962. Citing the fact that retardation can occur in any family, "poor or rich, of doctors, lawyers, writers, men of genius, presidents of corporations --- the President of the United States," she even singled out the ground-breaking efforts of Pearl Buck. In her words: “Nobel prizewinning novelist Pearl Buck, in a small volume called The Child Who Never Grew, has written a moving account of her efforts to find a good life for her mentally retarded daughter" . Shriver’s article was laced with photographs and was titled “Hope for Retarded Childen.”
Buck's efforts also had an effect on the wife of French President Charles de Gaulle, who said she had carried a similar cross on her back and experienced the same sorrow as had the American author for many years . And then there was actress Dale Evans Rogers, the actress wife of very popular cowboy actor Roy Rogers. She wrote a book in 1953 describing a child in their family who had Down's syndrome. This book had exceptionally high sales and also helped to change attitudes about the retarded and loving parents that did their best to care for them .
Buck now adopted the philosophy that the future of the world lies in its children, and that even those children who are mentally handicapped should be treated with greater dignity and understanding. Nevertheless, and in a way consistent with her own unique personality, she appeared to feel more comfortable working with adults to achieve this goal than with the children themselves. As she explained it, the first step had to be for the parents to accept a child's condition. A later step would be to try to have these children accepted in the wider community.
Numerous awards were given to Buck for her landmark efforts with the retarded. There were also countless personal letters of thanks. One of the more visible tokens of appreciation was a hand-painted doll from Japan, awarded to her by the Association of Parents of the Mentally Retarded in Japan. This doll was proudly put on display at the Pearl S. Buck Foundation in Philadelphia, where other awards, acknowledgements, and gifts are also housed.
Theodore F. Harris once wrote: "Everything this woman has accomplished in her life has been her answer to the world on a subject that concerns her" . As for her daughter Janice Walsh, she had this to say:
As a public figure, she was able to reach out to all peoples of the world, and show her compassion and concern. She was able to leave a legacy of simple caring for all mankind who would listen and accept her challenge. Would this legacy have been different if she had not given birth to Carol? It is impossible to say for sure, but I think that the answer is "yes." 
Pearl S. Buck knew the power of the pen and how influential she could be in drawing attention to human tragedies, changing attitudes, raising money for research, and disseminating pertinent information. Within her lifetime, she witnessed the initial advances that were made in detecting and treating PKU, the biochemical disorder that afflicted her daughter Carol and left her an invalid. Had Buck lived longer, she would have been pleased to discover just how much scientists had accomplished by the start of the twenty-first century, and how enthusiastic the scientific community could be when called together to exchange information at conferences and in books like this one.
[i] The quotations from The Child Who Never Grew come from the 1992, second edition of Pearl S. Buck’s book.
[ii] At the time of Carol’s birth, it had been discovered that Pearl S. Buck had a uterine tumor, for which she underwent a hysterectomy. Unable to have more biological children, Pearl S. Buck adopted several children, the first of whom was Janice. Carol's disability did not appear to be a major contributor to Buck's decision to adopt her later children, especially those who were orphaned Asian-American children. According to Harris , her need to adopt was partly driven by the ever increasing loneliness in her life: "There was, of course, no comfort in the retarded child, for she did not respond in any way to efforts to train and teach her except to become tired and nervous."
[iii] (John) Lossing Buck and Pearl Sydenstricker were married in 1917. Although the couple remained married for 18 years, Pearl S. Buck realized early on she should not have married Lossing, who was not addicted to books and, in her mind, was not her intellectual equal. "Did you ever try to live just with a handsome face?" asked Buck . Lossing Buck was noticeably absent from The Child Who Never Grew. According to Janice Walsh (1992), this omission was partly due to the fact that the couple was already growing apart when the Carol was born. Following the couple’s divorce in 1935, there was almost no communication between Lossing and his ex-wife. Lossing lived out his life in China and fathered two children after he remarried. Neither had PKU.
 P.S. Conn, Pearl S. Buck: A Cultural Biography, Cambridge University Press, Cambridge, UK, 1996, pp. 132.
 P.S. Buck, The Good Earth, Pocket Books, New York, 1994 (Original work published John Day Co., New York, 1931).
 P.S. Buck, The Child Who Never Grew, Ladies Home J (1950, May) 35, 146, 147, 150, 152, 156, 159, 160, 163-165, 167, 169, 171.
 P.S. Buck, The Child Who Never Grew, The Training School at Vineland, Vineland, NJ, 1950.
 P.S. Conn, Pearl S. Buck: A Cultural Biography, Cambridge University Press, Cambridge, UK, 1996, pp. 111-112.
 M.M. Jablow, Introduction, in: P.S. Buck, The Child Who Never Grew (2nd ed.), Woodbine House, Inc., Bethesda, MD, 1992, pp. 10.
 P.S. Buck, The Child Who Never Grew, Woodbine House, Inc., Bethesda, MD, 1992, p. 32. (Original work published by The Training School at Vineland, Vineland, NJ, 1950).
 P.S. Buck, The Child Who Never Grew, Woodbine House, Inc., Bethesda, MD, 1992, p. 36-37. (Original work published by The Training School at Vineland, Vineland, NJ, 1950).
 P.S. Buck, The Child Who Never Grew, Woodbine House, Inc., Bethesda, MD, 1992, p. 45. (Original work published by The Training School at Vineland, Vineland, NJ, 1950).
 T.F. Harris, Pearl S. Buck: A biography, John Day Co., New York, 1969, p. 119.
 P.S. Buck, The Child Who Never Grew, Woodbine House, Inc., Bethesda, MD, 1992, p. 62. (Original work published by The Training School at Vineland, Vineland, NJ, 1950).
 T.F. Harris, Pearl S. Buck: A biography, John Day Co., New York, 1969, p. 144.
 T.F. Harris, Pearl S. Buck: A biography, John Day Co., New York, 1969, p. 279.
 J.C. Walsh, Afterword, in: P.S. Buck, The Child Who Never Grew (2nd ed.), Woodbine House, Inc., Bethesda, MD, 1992, pp. 91-107.
 S.E. Christ, Asbjørn Følling and the discovery of phenylketonuria, J. Hist. Neurosci.. 12 (2003) 44-54.
 T.F. Harris, Pearl S. Buck: A biography, John Day Co., New York, 1969, p. 186.
 J.C. Walsh, Afterword, in: P.S. Buck, The Child Who Never Grew (2nd ed.), Woodbine House, Inc., Bethesda, MD, 1992, pp. 97-98.
 J.C. Walsh, Afterword, in: P.S. Buck, The Child Who Never Grew (2nd ed.), Woodbine House, Inc., Bethesda, MD, 1992, pp. 101.
 T.F. Harris, Pearl S. Buck: A biography, John Day Co., New York, 1969, p. 123.
 T.F. Harris, Pearl S. Buck: A biography, John Day Co., New York, 1969, p. 138.
 P.S. Conn, Pearl S. Buck: A Cultural Biography, Cambridge University Press, Cambridge, UK, 1996.
 J.C. Walsh, Afterword, in: P.S. Buck, The Child Who Never Grew (2nd ed.), Woodbine House, Inc., Bethesda, MD, 1992, pp. 106.
 P.S. Conn, Pearl S. Buck: A Cultural Biography, Cambridge University Press, Cambridge, UK, 1996, p. 102.
 T.F. Harris, Pearl S. Buck: A biography, John Day Co., New York, 1969, p. 84-85.
 P.S. Buck, The Good Earth, Pocket Books, New York, 1994 (Original work published John Day Co., New York, 1931), p. 161.
 P.S. Buck, The Good Earth, Pocket Books, New York, 1994 (Original work published John Day Co., New York, 1931), p. 199.
 P.S. Buck, The Good Earth, Pocket Books, New York, 1994 (Original work published John Day Co., New York, 1931), p. 298.
 P.S. Conn, Pearl S. Buck: A Cultural Biography, Cambridge University Press, Cambridge, UK, 1996, p. 124.
 P.S. Buck, My Several Worlds, John Day Co., New York, 1954.
 P.S. Buck PS, G.T. Zarfoss, The Gifts They Bring: Our Debt to the Mentally Retarded, John Day Co., New York, 1965.
 P.S. Buck, The Time is Noon, John Day Co., New York, 1967, p. 287.
 P.S. Buck, The Time is Noon, John Day Co., New York, 1967, p. 330-331.
 E.K. Shriver, Hope for retarded children, Sat Eve Post 235 (1962) 71-75.
 J.W. Trent Jr., Inventing the Feeble Mind: A History of Mental Retardation in the United States, University of California Press, Berkeley, CA, 1994.
 T.F. Harris, Pearl S. Buck: A biography, John Day Co., New York, 1969, p. 297.
 J.C. Walsh, Afterword, in: P.S. Buck, The Child Who Never Grew (2nd ed.), Woodbine House, Inc., Bethesda, MD, 1992, pp. 107.
 T.F. Harris, Pearl S. Buck: A biography, John Day Co., New York, 1969, p. 125.
 T.F. Harris, Pearl S. Buck: A biography, John Day Co., New York, 1969, p. 82.