SUMMARY 



77 



The thirty years since Hitzig's work cannot be 

 put here, for they would take a volume to them- 

 selves. There have been, now and again, differ- 

 ences of interpretation of this or that fact, diversities 

 of results, and problems too hard to solve, and other 

 difficulties, such as befall all the natural sciences ; 

 but these imperfections amount to very little, when 

 the whole result comes to be reckoned up. The 

 marvel is that the work is so nearly perfect, seeing 

 its immeasurable complexity. 



Let any man, who has but touched the study of 

 physiology, consider what is involved in even the 

 most superficial observation of the simplest facts of 

 the nervous system : for instance, the ordinary 

 nerve-muscle preparation that is taught to every 

 medical student, or the microscopic structure of the 

 spinal cord, or the Wallerian method. Or let him 

 consider how the physiology of the nervous system 

 has been founded on the lower forms of life : the 

 work of Romanes and others on the Medusa and 

 the Echinodermata, and Huxley's work in biology, 

 and the endless chain of forces that are alike in 

 man and in jelly-fishes. Then let him try to esti- 

 mate the output of hard thinking, for the advance 

 from lower to higher structures, and up to man ; 

 the vigilant criticism of all theories and foregone 

 conclusions, the incessant self-judgment and weari- 

 some doubts and disputes all the way, elusiveness 

 of facts, and vagueness of words. And the results 

 thus wrung out of science had still to be stated 

 in terms of practice, and tested by the facts of 

 medicine, surgery, and pathology, and used in 



