Editorial, Problems of Coniparafivc A^ci/rolo^'v. lot 



has been to subordinate more and more structures and func- 

 tions to the purposes of the head. Moreover, it has been 

 more or less distinctly seen that the solution of the anatomi- 

 cal and then the physiological problems connected with the 

 head is essential to the completion of any systematic theory 

 respecting the connection between body and mind. It has 

 been felt that if the head, with its structures so obviously 

 intended to serve as an avenue of expression for the mind, 

 can be explained as a compound of the somewhat modified 

 simple elements occurring in each segment of the body of a 

 lower animal, then the mind itself might prove but the sum 

 of all the functions represented by these several organs, 

 though rendered never so " psychical," by reason of their 

 complex interaction. Probably few biologists would care to 

 commit themselves to so extreme a view as this, yet the great 

 problem remains: what is the relation between the functions 

 of the nervous elements and the phenomena of mind as such, 

 or, in other words, just what has the nervous system, and 

 especially the brain, to do with thought. The analysis 6f 

 the head may of course be pursued from different stand- 

 points. When it was seen that many of the structures of the 

 head, such as the upper and lower jaws and the hyoid appa- 

 ratus were modified visceral arches, it was but natural that 

 the attempt should be made to apply the same analysis to the 

 skull itself. The failure of the now celebrated vertebral 

 theory of the skull by no means discouraged investigators 

 from the attempt to discover the law of combination in 

 accordance w^ith which the region has differentiated. 



The facts that much of the head lies beyond the end of the 

 chorda, and that the nerves of special sense seem to conform 

 to a different plan of structure and obey a peculiar law of 

 development, have led to the separation of a primitive 

 anterior part of the head and brain and a secondarily 

 acquired posterior portion. The original metamerism of the 

 head may fail to exhibit itself in the skull, partly because so 

 many extraneous elements have been from time to timeamal- 



