i6o Journal of Comparative Neurology, 



The pathological method is one of experiment; indeed 

 pathological conditions are all experiments — nature's ex- 

 periments — ready at hand for investigation and often 

 more ingenious than we could invent. The great power 

 of the pathological method is that phenomena are often 

 simplified by being split up into their components. A set 

 of greatly complicated phenomena is detached from the 

 others, is dropped out of the intricate series, becomes 

 isolated and thus amenable to control. Having be- 

 fore us isolated and accentuated components of the intri- 

 cate phenomena forming pathological processes, we can 

 often by means of experiment modify these detached 

 factors and still further analyze them into simpler ele- 

 ments. Finally by studying different phases of a patho- 

 logical process the component factors of a phenomenon 

 are reduced to simplest terms, analyzed into elementary 

 units. This accomplished, we may undertake a synthesis 

 of the factors, arranging them with relation to cause and 

 effect, and thus arrive at a formula or generalization 

 which will not only explain the single phenomenon, but 

 also all other phenomena of the same kind. The patho- 

 logical method, then, stands foremost in scientific inves- 

 tigation of organic phenomena, even of the normal 

 manifestations. 



Comparative neurology, like all other sciences that 

 deal with life phenomena, must use similar methods, 

 among which the methods of experimental pathology play 

 an important role. But comparative neurology uses 

 largely the pathological method, in the wider sense of the 

 term; for in the nervous systems of the lower animals 

 we perceive again and again the analogies of pathological 

 conditions with the only difference that they are spread 

 out in time and extended along the phylogenetic pathway 



