VEGETABLE ALKALIES, ETC. 177 



The effects of these substances are singularly 

 varied; from the mildest form of the action of 

 aloes, to the most terrible poison, strychnia, we 

 observe an endless variety of different actions. 



With the exception of three, all these substances 

 produce diseased conditions in the healthy organ- 

 ism, and are poisonous in certain doses. Most of 

 them are, chemically speaking, basic or alkaline. 



No remedy, devoid of nitrogen, possesses a poison- 

 ous action in a similar dose.* 



85. The medicinal or poisonous action of the 

 nitrogenised vegetable principles has a fixed rela- 

 tion to their composition ; it cannot be supposed 

 to be independent of the nitrogen they contain, 

 but is certainly not in direct proportion to the quan- 

 tity of nitrogen. 



Solanine (38), and picrotoxine (39), which con- 

 tain least nitrogen, are powerful poisons. Quinine 

 (40) contains more nitrogen than morphia (41). 

 Caffeine (42), and theobromine, the most highly 

 nitrogenised of all vegetable principles, are not 

 poisonous. 



86. A nitrogenised body, which exerts, by means 

 of its elements, an influence on the formation or on 

 the quality of a secretion, must, in regard to its 



* This consideration or comparative view has led lately to a 

 more accurate investigation of the composition of picrotoxine, 

 the poisonous principle of cocculus indicus ; and M. Francis has 

 discovered the existence of nitrogen in it, hitherto overlooked, 

 and has also determined its amount. 



