THE RELATIONS OF THERAPEUTICS 167 



entirely to the nineteenth century. To John Hunter in England 

 and Bichat in France belongs the credit of freeing pathological 

 anatomy from the brainless descriptive scientists, and of forming 

 it into the necessary basis for every form of progress in therapeu- 

 tics. From this time until Virchow's labors, the decisive import- 

 ance of which is recognized impartially by all nations, pathological 

 anatomy has exercised a great influence upon medical activity. 

 Cellular pathology especially, in spite of all former battles and 

 present attacks, will form the basis of every experimental and 

 therapeutic observation, though some of the views concerning it 

 may undergo modification through the progress of science, and 

 opinions which Virchow himself could not accept may be brought 

 forward again. The scientific question which appeared as a result 

 of cellular pathology is the question of the cause and symptomato- 

 logy of disease. Nothing can be more suitable in treating this ques- 

 tion than to quote Virchow's own words: 



"An elementary pathological process in the sense of cellular 

 pathology appears thus: an external influence acts upon a living 

 cell and alters it in a mechanical or chemical way. The external 

 influence is the causa externa, or as we simply express it, the cause 

 of disease : the altered condition is called passio, disease. If now, 

 in consequence of the change undergone, an action (actio s. reactio) 

 takes place in the living cell, this change is called a state or irrita- 

 tion (irritamentum) , and the cause of disease irritants. If, on the 

 other hand, no action ensues, if the condition is limited to the 

 change "suffered" by the cell, we have to do with a mere disturb- 

 ance (lacsio) or paralysis. Since, however, the same cause can 

 evoke irritation in one cell, merely a disturbance in another, and 

 even paralysis in a third, we assume a certain difference of the in- 

 ternal arrangement to be the cause of this varying behavior. Thus 

 we come to the internal cause or predisposition." 



But these words, spoken in 1880, must be modified according to 

 present experience. According to Virchow the causa externa is 

 the cause of disease. The irritant acting upon the organism is under 

 all circumstances the morbific factor according to this assumption. 

 We do not wish to play with words. If, indeed, this foreign intrud- 

 ing agent produces a destruction of the cell-power or a morbid 

 modification of it, it obviously must be regarded as the actual cause 

 of disease. But when, for instance, we see that the invading body 

 produces only an entirely local irritation, or, although capable of 

 reproduction, as is the case with bacteria, no proliferation occurs, 

 it becomes difficult to consider the same factor as the cause of dis- 

 ease in all instances. Virchow terms this phenomenon of indolence 

 of the cell towards the intruder a want of predisposition; accord- 

 ing to the school of bacteriologists, however, the cell is not a cul- 



