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 
