8o6 THE POPULAR SCIENCE MONTHLY. 



which coordinates and regulates these physiological units into an or- 

 ganic whole. 



In fact, the body is a machine of the nature of an army, not of that 

 of a watch, or of an hydraulic apparatus. Of this army, each cell is a 

 soldier, an organ a brigade, the central nervous system headquarters 

 and field telegraph, the alimentary and circulatory system the commis- 

 sariat. Losses are made good by recruits born in camp, and the life 

 of the individual is a campaign, conducted successfully for a number 

 of years, but with certain defeat in the long-run. 



The efficacy of an army, at any given moment, depends on the 

 health of the individual soldier, and on the perfection of the machinery 

 by which he is led and brought into action at the proj^er time ; and, 

 therefore, if the analogy holds good, there can be only two kinds of 

 diseases, the one dependent on abnormal states of the physiological 

 units, the other on perturbation of their coordinating and alimentative 

 machinery. 



Hence, the establishment of the cell theory, in normal biology, was 

 swiftly followed by a " cellular pathology," as its logical counterpart. 

 I need not remind you how great an instrument of investigation this 

 doctrine has j^roved in the hands of the man of genius, to whom its 

 development is due ; and who would probably be the last to forget 

 that abnormal conditions of the coordinative and distributive machin- 

 ery of the body are no less important factors of disease. 



Henceforward, as it appears to me, the connection of medicine with 

 the biological sciences is clearly defined. Pure pathology is that 

 branch of biology which defines the particular perturbation of cell-life, 

 or of the coordinating machinery, or of both, on which the phenomena 

 of disease depend. 



Those who are conversant with the present state of biology will 

 hardly hesitate to admit that the conception of the life of one of the 

 higher animals as the summation of the lives of a cell aggregate, 

 brought into harmonious action by a coordinative machinery formed 

 by some of these cells, constitutes a permanent acquisition of physio- 

 logical science. But the last form of the battle between the animistic 

 and the physical views of life is seen in the contention whether the 

 physical analysis of vital phenomena can be carried beyond this point 

 or not. 



There are some to whom living protoplasm is a substance even such 

 as Harvey conceived the blood to be, '"'' swmma cum providentia et 

 intellectu infinem certum agens, quasi ratiocinio quodam " ; and who 

 look, with as little favor as Bichat did, upon any attempt to apply the 

 principles and the methods of physics and chemistry to the investiga- 

 tion of the vital processes of growth, metabolism, and contractility. 

 They stand upon the ancient ways ; only, in accordance with that 

 progress toward democracy which a great political writer has declared 

 to be the fatal characteristic of modern times, they substitute a repub- 



