Note 22 — CAUSES OF IDIOCY.

Dr. Hammond, Professor of Diseases of the Nervous System at Bellevue College, New York, has published some interesting statistics in reference to the relative weight of the brain, as compared with that of the body, in various classes of vertebrate animals, by which he shows that there is no definite relation between the intelligence of animals and the absolute or relative size of the brain. Thus, he says, "the canary bird and the Arctic sparrow have brains proportionately larger than those of any other known animals, including man, and yet no one will contend that these animals stand at the top of the scale of mental development. Man, who certainly stands at the head of the class of mammals, and of all other animals, so far as mind is concerned, rarely has a brain more than one-fiftieth the weight of the body, a proportion which is much greater in several other mammals, and is, as we have seen, exceeded by many of the smaller birds."