450 ANNUAL, KEPOET SMITHSONIAN INSTITUTION, IdV.). 
Among achoiidroi^iastic human dwarfs both breeds occur, but the 
" bulldog " form is much more common than the " dachshund " type. 
The shortening of limbs with retraction of the nasal region of the 
face — pug-face, or prosopin, we may call the condition — has a ver}^ 
direct interest for anthropologists, seeing that short limbs and a long- 
trunk are well recognized racial characteristics of the Mongol. In 
the second kind of dwarfism, which we have reason to regard as due 
to a functional defect of the thyroid, the Mongolian traits are so 
apparent that the sufferers from this disorder are known to medical 
men as " Mongolian idiots," for not only is their groAvth stunted but 
their brains also act in a peculiar and aberrant manner. Dr. Lang- 
don Down, who gave the subjects of this peculiar disorder the name 
"Mongolian idiots" 55 years ago, knew nothing of the modern doc- 
trine of internal secretions, but that doctrine has been applied in 
recent years by Dr. F. G. Crookshank (The Universal Medical Rec- 
ord, vol. iii, p. 12, 1913) to explain the features and condition of 
Mongoloid imbecile children. Some years ago ( Journ. of xVnat. and 
Physiol., 1913) I brought forAvard evidence to show that Ave could 
best explain the A^arious forms of anthropoid apes by applying the 
modern doctrine of a growth-controlling glandular mechanism. In 
the gorilla we see the effects of a predominance of the pituitary ele- 
ments ; in the orang, of the thyroid. The late Prof. Klaatsch tried 
to account for the superficial resemblances betAveen the Malay and 
the orang by postulating a genetic relationship between them ; for a 
similar reason he cleriA^ed the Negro type from a gorilline ancestr3^ 
Occasionally we see a man or AA^oman of supposedly pure European 
ancestry displaying definite Mongoloid traits in their features. "We 
liaA^e been in the habit of accounting for such manifestations by the 
theory, at one time A^ery popular, that a Mongoloid race had at one 
time spread oA^er Europe and that Mongoloid traits Avere atavistic 
recurrences. An examination of the human remains of ancient 
Europe yields no evidence in support of a Turanian or Mongol inva- 
sion of Europe. 
All these manifestations to which I have been directing your atten- 
tion — the sporadic manifestation of the Mongoloid characters in dis- 
eased children and in healthy adult Europeans, the generic characters 
which separate one kind of ape from another, the bodily and mental 
features which mark the A^arious races of mankind — are best ex- 
plained by the theory I am supporting, namely, that the conforma- 
tion of man and ape and of every A^ertebrate animal is determined by 
a common growth-controlling mechanism which is resident in a sys- 
tem of small but complex glandular organs. We must noAv look 
somewhat more closely into the manner in which this growth-regulat- 
ing mechanism actually works. That we can do best by taking a 
glimpse of a research carried out by Bayliss and Starling in the open- 
