MEDICINAL ACTION. 145 



writing, and smoking indefatigably, whereas I 

 have been thus engaged since three o'clock this 

 morning, the hour being now four o'clock p.m. ? 

 Thirteen hours' thinking fixedly, composing, 

 transcribing, translating, and smoking all the 

 while ; and add to this another item, that I had 

 been writing until midnight, when I retired for 

 the repose of three short hours. This may be 

 called abuse — but I know it not to be so in my 

 case — as ray constitution is capable of greater 

 endurance. 



" Witli some constitutions smoking never agrees, but 

 both Dr. Pereira, and Dr. Christison in his ' Treatise on 

 Poisons,' agree that ' no well-ascertained ill effects have 

 been shown to result from the habitual practice of 

 smoking.' Dr. Prout, an excellent chemist and a phy- 

 sician of extensive medical experience, whom all his scien- 

 tific contemporaries held in much esteem, was of a different 

 opinion. But even he expresses himself obscurely as to 

 its being generally deleterious when moderately indulged 

 in. I give Dr. Prout's own words : — * Tobacco disorders 

 the assimilating functions in general, but particularly,%s 

 I believe, the assimilation of the saccharine principle. 

 Some poisonous principle, probably of an acid nature, is 

 generated in certain individuals by its abuse, as is evident 

 from their cachetic looks, and from tlie dark and often 

 greenish-yellow tint of the blood. The severe and peculiar 

 dyspeptic symptoms sometimes produced by inveterate 

 snuff-taking are well known, and I have more than once 



