THE PRESENT ASPECT OF MEDICINE. 341 



advance in physiology has not only corroborated the ancient 

 doctrine of the interdependence of the different textures and 

 organs on one another, as constituent parts of the organism, 

 but has, in addition, brought prominently under view the 

 independent characteristics, not of organs merely, but of 

 textures, with their constituent elements and parts. As 

 respects a given healthy or morbid process, we are now 

 attaining to the power of distinguishing the respective 

 independent actions of the blood (not of the blood viewed as 

 a whole merely, but of its elements), of the capillary, of the 

 nerve-filament, of the proper texture of the part ; and 

 again, not of that texture viewed as a whole, but of its 

 nuclei, of its internuclear substance (or, if you prefer the 

 term, intercellular substance), and of the independent terri- 

 tories themselves of that substance. 



It thus appears that a healthy process consists of a 

 number of interdependent actions, each of which, however, 

 is so far independent that it admits of being separately 

 examined and influenced. In like manner, one or more of 

 these so-far independent actions admitting of being unduly 

 influenced, some one or more morbid phases of the originally 

 healthy process may be induced. But since the so-far 

 independent constituent actions of the process admit of 

 being individually examined and influenced in both healthy 

 and morbid phases, an intelligible principle is thus supplied 

 for our therapeutic interference. For no principle in 

 physiology is more firmly established than this, that certain 

 natural and artificial substances, when introduced into the 

 living body, increase or diminish, promote or restrain, the 

 so-far independent constituent actions of its healthy processes. 

 Those substances do not influence any one process as a 

 whole, but only one OT more of the so-far independent 

 constituent actions of that process. One of those substances 

 may influence only the action of the ultimate nerve-filament ; 



