372 BIOLOGICAL SCIENCES AND MEDICINE xiv 



From this point of view, pathology is the 

 analogue of the theory of perturbations in astron- 

 omy; and therapeutics resolves itself into the 

 discovery of the means by which a system of forces 

 competent to eliminate any given perturbation may 

 be introduced into the economy. And, as pathology 

 bases itself upon normal physiology, so therapeutics 

 rests upon pharmacology; which is, strictly speak- 

 ing, a part of the great biological topic of the influ- 

 ence of conditions on the living organism, and has 

 no scientific foundation apart from physiology. 



It appears to me that there is no more hopeful 

 indication of the progress of medicine towards the 

 ideal of Descartes than is to be derived from a com- 

 parison of the state of pharmacology, at the present 

 day, with that which existed forty years ago. If 

 we consider the knowledge positively acquired, in 

 this short time, of the modus operandi of urari, of 

 atropia, of physostigmin, of veratria, of casca, of 

 strychnia, of bromide of potassium, of phosphorus, 

 there can surely be no ground for doubting that, 

 sooner or later, the pharmacologist will supply the 

 physician with the means of affecting, in any de- 

 sired sense, the functions of any physiological ele- 

 ment of the body. It will, in short, become pos- 

 sible to introduce into the economy a molecular 

 mechanism which, like a very cunningly-contrived 

 torpedo, shall find its way to some particular group 

 of living elements, and cause an explosion among 

 them, leaving the rest untouched. 



