238 ORIGIN AND NATURE OF LIFE 



greatly embarrassed, and the product is a 

 peculiar type of dwarf called a cretin, found 

 frequently in certain Alpine valleys. Stray 

 cretins are to be found in all large centres of 

 population, and in a typical cases there can 

 be no failure of recognition. The height is 

 stunted down to four feet or less, the head 

 and face are broad, and on account of failure 

 or misplacement of the natural folds of the 

 skin the features are lacking in expression. 

 The hair and skin are dry and lustreless, and 

 the eyes are dull, the whole indicating even to 

 a lay person a condition of idiocy. And the 

 undeveloped mind is truly indicated by these 

 outward appearances. The hands even are 

 large and clumsy in shape, and the fingers 

 broad and stub-ended. All this change is 

 produced by a failure in the secretion of a 

 small inconspicuous gland in the neck, which 

 in a grown man does not exceed an ounce 

 in weight. Short of complete cretinism, 

 backwardness in intelligence and growth, in 

 many of our mentally defective children are 

 due to diminished thyroid secretion, and 

 such cases show wonderful improvement not 

 only in growth and physical vigour, but in 

 mental intelligence also, when they are put 

 upon a course of treatment with thyroid 

 glands of the sheep. For the active material 



