18 Dr. H. A. Cummins — A Theory af Vegetable Antitoxins. [Jan. 



coal gas, &c., seem to have an influence on plants like that produced on 

 animals by narcotic poisons : other gases as sulphurous and hydrochloric 

 acid appear to resemble the action of irritants upon animals (Bentley, 

 Manual of Botany, p. 806). 



Sec. III. Antiseptics — Quinine, etc. — Constitution of Protoplasm 

 IN different species. 



We next pass to the consideration of antiseptics or substances 

 which kill or check the growth of fermentative organisms : amongst 

 these I mention salicylic acid, thymol, and eucalyptus-oil (essential 

 principle). 



The Eucalyptus globulus is well known as a purifier of the soil and 

 it is probable that the essential principle of the oil is antitoxic. If it 

 does not exist in the plant in its ordinary form, it is very speedily con- 

 verted into this form on exposure to the air, probably by the action of 

 a ferment, as takes place in the coagulation of blood in animals. 



We now turn to Cinchona and Ipecacuanha, These two plants 

 grow in localities where the diseases for which they are used as remedies 

 prevail. The fact is remarkable even if the two poisons cannot be 

 shown to produce the two diseases and remedies respectively in plants 

 and animals. The quinine being antitoxic in the plant is capable of 

 supplying, to a certain extent, the want of antitoxin in man. We know 

 that plants growing side by side in the same soil produce different 

 secretions. This shows us how the constitution of protoplasm varies 

 in different species : from this we can see how one poison may produce 

 many kinds of antitoxins in as many differently constituted plants. 



We may infer that the poisonous principles of many plants such 

 as Nux-vomica, Gonium, Digitalis, &c., are antitoxic substances and not 

 altogether as has been stated a protection for the foliage of the plant 

 against its destruction by herbivorous animals. 



Sec. IV. Alteration in character op secretions by change of 



environment. 

 We must next consider the alteration in the character of secretion 

 caused by change of environment. Gicuta virosa and (Enanthe crocata 

 wliich are poisonous in most districts in England are harmless when 

 grown near Edinburgh. The common mushroom (Agaricus arvensis) 

 when grown in England is a comestible article, but in Italy and 

 Hungary it is avoided on account of its possessing a poisonous principle 

 (Bentley, Manual of Botany, pages 824 and 825). The toxic resin of 

 Cannabis sativa when grown in England is very small or altogether 

 absent : but the variety indica, which is considered by most authorities 



