82 CROONIAN LECTURES 



in any of the motions of the body must arise 

 from some other form of energy, and that this 

 must ultimately be traced up to the chemical 

 energy which enters with the food and air, 

 then the action of medicines in increasing or 

 diminishing or altering the action of oxygen in 

 the different textures must be at least one of 

 the most important questions in therapeutics. 



Let me for a moment take the most directly 

 chemical of all medicines, alkalies and acids, 

 and let me try to show you that they are 

 capable of taking a part in oxidation ; and, 

 from this experiment regarding the actions of 

 acids and alkalies out of the body, perhaps you 

 will be inclined to agree with me that they are 

 capable of playing opposite parts in the oxida- 

 tion which is going on everywhere in the body. 



I have here an organic matter, grape-sugar, 

 and oxygen in the oxide of copper, precipitated 

 from the sulphate by alkali, which I can bring 

 into contact with each particle of the organic 

 matter. In each of these glasses, the same 

 amount of sugar and oxygen and alkali is 

 present. I will leave one glass as a standard 

 of comparison regarding the rate of oxidation 

 of the grape-sugar. To the other glasses I will 



