CHEMISTRY IN ITS RELATIONS TO MEDICINE. 217 



known as that of the latter. Years after the effects produced by the 

 inhalation of chloroform were discovered, Liebreich reasoned thus : If 

 chloral breaks up in alkaline liquids into chloroform and formic acid, 

 why should it not break up in the same way when introduced into the 

 animal system ? The conditions in the body are favorable for such a 

 decomposition the blood is an alkaline liquid and the chloral will dis- 

 solve in it. By means of this reasoning the discovery was made, and 

 there is no cause to doubt that the beneficial effects experienced from 

 chloral are due to the fact that the alkaline blood decomposes it, form- 

 ing chloroform and formic acid, the chloroform being thus introduced 

 into the system in a manner differing from that involved in the inhala- 

 tion process. 



As regards salicylic acid, its discovery was the result of a long 

 series of purely scientific investigations. For years Kolbe had been 

 trying to produce artificially in his laboratory some of the substances 

 which are found in nature. He strove faithfully and conscientiously 

 to accomplish his purpose, and at last he discovered a method which 

 enabled him to make oxalic acid ; and then, after the method was given, 

 the production of other similar acids was simply a question of the ap- 

 plication of the new method. Salicylic acid was among the products 

 thus formed. The acid had been known for a long time, but, as it 

 could be obtained only from the expensive oil of wintergreen, it 

 belonged to the rare substances. Kolbe's method of preparation, 

 however, furnished the substance in large quantities and at a low 

 price. 



The discovery of the valuable antiseptic properties of the acid was 

 a pure scientific discovery, and was due to purely chemical reasoning. 

 It was known that salicylic acid when heated breaks up directly into 

 carbolic acid and what is commonly called carbonic acid. It occurred 

 to Kolbe that possibly this property might be taken advantage of to 

 furnish a substitute for the objectionable carbolic acid. The results of 

 his experiments are well known : they were more satisfactory than he 

 had hoped for. He found that salicylic acid is an excellent antiseptic. 

 Though he has shown that, contrary to his expectation, the antiseptic 

 action possessed by the acid is not due to its breaking up into carbonic 

 and carbolic acid, still the action must be due to a similarity between 

 the chemical structures of the two acids ; and this similarity could not 

 have been detected without the aid of some of the most refined meth- 

 ods of scientific chemistry. It is safe to say that blind experiment, un- 

 guided by definite chemical principles, could not have led to this dis- 

 covery. 



Thus I have at least illustrated the truth of the remark I made a 

 few minutes since, to the effect that the discoveries of substances valu- 

 able in medicine are made by those engaged in the pursuit of pure 

 science. I am aware that the two examples thus referred to will not 

 suffice to furnish a perfect proof of the proposition ; but, if time per- 



