THE DISPARITY BETWEEN AGE AND DEVELOPMENT IN THE 
HUMAN FAMILY, ILLUSTRATED BY PRONOUNCED 
CASES DUE TO THYROID MALFORMATIONS. 
BY JAMES EREDEEIC CLAEKE. 
Plates XIX-XXVIII. 
The author of Rip Van Winkle has his hero awaken from the long 
sleep, an old man. The writer does not violate in fiction our conception 
of the uniform advancement, in human growth and development, from 
infancy to old age. So uniform is growth in children that we associate 
in our minds rather definite sizes and mental conditions with certain 
years from birth. Dress patterns are made for a three or an eight year 
old girl. A shoe merchant can usually select correct shoes for your boy 
if he is told the age. There is not great variation from the average age of 
the majority of the pupils in any particular grade of the common schools. 
(Note I). I find that the age of learning to walk, cutting the 
first tooth, of speaking words and forming sentences is comparative^ 
uniform among healthful children of the same class. (Note II.) 
However, all of us know of marked exceptions to this rule of uni- 
formity in development. A precocious child now and then varies widely 
from the average and seems far in advance of his calendar age; or a 
“backward” boy may begin dentition or walking months later than is 
usual for children. These marked variations are found in so-called 
“normal” individuals. Beyond this, abnormal variations occur, reach- 
ing from dwarfism to giantism in the physical or from inbecility to 
genius in the intellectual development. 
The causes of these variations in development are numerous; some 
acting throughout the individual’s life while others for a brief period 
delay or advance the mental or physical growth of the child. It is my 
purpose to present for your consideration but one — perhaps the most 
striking — example of variation in development. A condition, called 
Cretinism, that has been studied to some extent by ph5"sicians in their 
professional work, but, as far as I can learn, is as yet almost unnoticed' 
by teachers and psychologists. It may be healthful in these days of popu- 
lar “mental science” to study an intellectual abnormality due to a mater- 
ial cause and corrected by a material treatment. 
In some parts of Europe it is common to find these individuals who 
at an early age experience an almost complete cessation of physical and 
mental development due to a congenital absence or loss of function of 
the thyroid gland. The cause of the condition was for long mistakenly 
supposed to be some peculiarity in the drinking water or the soil. 
( 257 ) 
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