172 BIOLOGICAL ASPECTS OF HUMAN PROBLEMS 



to some singular paradoxes. Dr. Crile cut off the 

 head of a dog, but so quickly reestablished the 

 blood supply in the trunk and extremities that these 

 continued to live and functionate for twenty-four 

 hours. A corresponding restoration of function in 

 the brain by similar methods has not been accom- 

 plished and appears impossible. What shall we say 

 of Dr. Crile's decapitated dog? Was he alive or 

 dead after decapitation? The answer must depend 

 upon our conception of death. If we attach great 

 weight to the life of the less noble tissues, the dog 

 must be regarded as being alive despite the loss of 

 the head. On the other hand, if we attach supreme 

 importance to the brain, to the function of conscious- 

 ness, and to the all-important part it plays in mak- 

 ing personality, we must answer that the dog was 

 dead despite the fact that the body was alive. This 

 is equivalent to conceding that personality is what 

 determines life. The fact that, in the experimental 

 case just cited, the personality in question is only that 

 of a dog does not alter the case; for there is little 

 doubt that the illustration of the dog could be suc- 

 cessfully repeated in the case of man. 



If we admit that the life of the brain is the essen- 

 tial feature of human life, we have to make some 

 further admissions based on the dissociation of func- 

 tion analogous to that just noted in the case of the 

 dog. We have to admit that, however well the body 

 may otherwise be preserved, any changes in the 

 brain that tend to degrade personality are changes 



