The etiology of Mongolian idiocy is unknown. The various suggestions which have been made with regard to the causation of this peculiar form of infantilism remain as yet but tentative proposals. This paper is concerned with a discussion of but one of the proposed etiologies, namely, syphilis. The theories thus far propounded may be summarized as follows:
Mongolism is caused by maternal exhaustion, because the Mongolian children are usually the last of large families.
Mongolism is caused by pressure on the basal ganglia of the brain, in proof of which it is cited that (a) the anteroposterior diameter of the cranium is shorter than in normal children, (b) the occiput is usually flat, and (c) the weight of the medulla relative to the remainder of the brain is less than in normal brains.
Mongolism is caused by agenesia of the cortex cerebri, because (a) the cortex is thinner than in