294 SCIENCE PROGRESS 



privileges, should it be found desirable by the properly con- 

 stituted authorities. Some of these practical problems concern- 

 ing mental hygiene will, I trust, be better understood by the 

 public, if they will consider the subject from the physiological 

 and medical points of view, as well as from the economic and 

 political. 



Mental Hygiene from a Physiological Standpoint 



Structure and Development of the Brain. — The most striking 

 anatomical distinction of man from the anthropoid apes is the 

 enormous increase in the development of the great brain — the 

 cerebrum — and this increase in size is due almost entirely to an 

 enlargement of that part of the great brain which occupies the 

 cranial vault and gives to man a dome-like shape to the skull. 



Gall, the phrenologist, more than one hundred years ago, 

 was the first to point out that that part of the brain with which 

 the higher mental activities are connected must be the cerebral 

 hemispheres. He said : " If we compare man with animals we 

 find that the sensory functions of animals are much finer and 

 more highly developed than in man ; in man, on the other hand, 

 we find intelligence much more highly developed than in animals. 

 Upon comparing the corresponding anatomical conditions we 

 see," he said, " that in animals the deeper situated parts of the 

 brain are relatively more developed and the hemispheres less 

 developed than in man ; in man the hemispheres so surpass in 

 development those of animals that we can find no analogy." Gall 

 moreover studied the brains of imbeciles and demented persons, 

 and was the first to point out that the disorder and deficiency of 

 mind of one, and the disorder and loss of mind of the other, 

 should be correlated with the deficient development of the hemi- 

 spheres in the feeble-minded imbecile and the destruction of the 

 hemispheres in the demented lunatic. 



Unfortunately Gall's imagination outstripped his judgment 

 and he wrecked his fame as a scientist by associating mental 

 traits of character with conditions of the skull ; then, encouraged 

 by a wide-spread wave of popular sympathy in the endeavour 

 to materialise and localise the functions of mind, he launched into 

 speculative hypothesis unsupported by facts. His doctrine of 

 phrenology was shown to be absolutely illogical ; but the 

 importance of his work in showing that the brain was the organ 

 of mind has since been recognised. 



