vestigators who have done very careful work do 

 not consider that nicotine is the toxic element, 

 but the substance called pyridine which is de- 

 rived from it. 



Dr. Bush (quoted below) referring to this 

 matter says: 



"From a review of the literature it would ap- 

 pear that extensive studies had been made as to 

 the effects on living organisms of the alkaloid, 

 nicotine. From such studies a great number 

 of writers, especially laymen, have adopted the 

 hasty conclusion that tobacco smoking entailed 

 like results. 



"Comparatively few studies have been made 

 of the effects of tobacco smoking on human be- 

 ings ; and such as have been made fail to state 

 if the tobacco used or the smoke produced was 

 examined for nicotine or its congeners. The 

 absence of an examination necessarily causes 

 some doubt in the causative faction of the 

 phenomena. Some authors are rather inclined 

 to conclude that nicotine alone is the pathogenic 

 factor in tobacco smoking, but since the pres- 

 ence of nicotine per se in tobacco smoke is de- 

 batable and since other toxic substances are 

 demonstrable, it would seem as if the whole sub- 

 ject still remained open for investigation." 



The nicotine contained in ordinary tobacco, 

 according to many authors, ranges from about 



182 



