606 



SCIENCE. 



[N. S. Vol. XIV. No, 355. 



changes through which both the brain and 

 its bony envelope have passed. Up to the 

 present little or no effort has been made to 

 contrast those parts of the cranial wall or 

 cavity which have been specially modified 

 by the cerebral growth-changes which are 

 peculiar to man. It may be assumed that 

 these changes have not taken place to an 

 equal extent, or indeed followed identically 

 the same lines in all races. 



Unfortunately our present knowledge of 

 cerebral growth and the value to be at- 

 tached to its various manifestations is not 

 so complete as to enable us to follow out to 

 the full extent investigations planned on 

 these lines. But the areas of cerebral cor- 

 tex to which man owes his intellectual su- 

 periority are now roughly mapped out, and 

 the time has come when the effect produced 

 upon the cranial form by the marked ex- 

 tension of these areas in the human brain 

 should be noted and the skulls of different 

 races contrasted from this point of view. 



To some this may seem .a return to the 

 old doctrine of phrenology, and to a certain 

 extent it is ; but it would be a phrenology 

 based upon an entirely new foundation and 

 elaborated out of entirely new material. 



It is to certain of the growth changes in 

 the cerebrum which I believe to be specially 

 characteristic of man, and which unques- 

 tionably have had some influence in de- 

 termining head-forms, that I wish particu- 

 larly to refer in this address. 



The surface of the human cerebrum is 

 thrown into a series of tortuous folds or 

 convolutions separated by slits or fissures, 

 and both combine to give it an appearance 

 of great complexity. These convolutions 

 were long considered to present no definite 

 arrangement, but to be thrown together in 

 the same meaningless disorder as is exhib- 

 ited in a dish of macaroni. During the 

 latter half, or rather more, of the century 

 which has just ended it has, however, been 

 shown by the many eminent men who have 



given their attention to this subject that 

 the pattern which is assumed by the convo- 

 lutions, while showing many subsidiary 

 differences, not only in different races and 

 different individuals, but also in the two 

 hemispheres of the same person, is yet ar- 

 ranged on a consistent and uniform plan in 

 every human brain, and that any decided 

 deviation from this plan results in an im- 

 perfect carrying out of the cerebral function. 

 In unraveling the intricacies of the human 

 convolutionary pattern it was very early 

 found that the simple cerebral surface of 

 the ape's brain in many cases afforded the 

 key to the solution of the problem. More 

 recently the close Btudy of the manner in 

 which the convolutions assume shape dur- 

 ing their growth and development has 

 yielded evidence of a still more valuable 

 kind. We now know that the primate 

 cerebrum is not only distinguished from 

 that of all lower mammals by the possession 

 of a distinct occipital lobe, but also by hav- 

 ing imprinted on its surface a convolution- 

 ary design which in all but a few funda- 

 mental details is different from that of any 

 other order of mammals. 



There are few matters of more interest to 

 those anthropologists who make a study of 

 the human skull than the relationship 

 which exists between the cranium and the 

 brain during the period of active growth of 

 both. Up to the time immediately prior to 

 the pushing out of the occipital lobe, or, in 

 other words, the period in cerebral develop- 

 ment which is marked by the transition 

 from the quadrupedal type to the primate 

 type of cerebrum, the cranial wall fits like 

 a tight glove on the surface of the enclosed 

 cerebrum. At this stage there would appear 

 to be a growth antagonism between the 

 brain and the cranial envelope which sur- 

 rounds it. The cranium, it would seem, 

 refuses to expand with a speed sufficient to 

 meet the demands made upon it for the ac- 

 commodation of the growing brain. In 



