The Evolution of the Sciences 



muscles. Thus the parallelism persists for the 

 three kingdoms of Nature, even down to ex- 

 ceptional cases. 



The action of poisons and anesthetics mani- 

 fests new analogies. Some bodies, such as a 

 weak solution of sodium carbonate, act as 

 excitants ; others, such as bromide of potassium, 

 dull the sensibility of a tin rod, as well as of a 

 carrot root or an animal tissue. Chloroform 

 vapour, chloral and formaline in solution, abolish 

 temporarily all sensibility and do not require 

 more than a minute to stupefy a carrot or a 

 radish. Finally, the action of poisons suppresses 

 beyond recovery every trace of electric response ; 

 some appear to have a universal action, such as 

 concentrated alkalis and acids, potassium cyan- 

 ide, and corrosive sublimate. Oxalic acid, which 

 is also poisonous for living beings, acts on metals 

 to such a degree that a solution of one in ten 

 thousand is sufficient to destroy every trace of 

 electric response in them. As is well known, 

 therapeutics furnish numerous examples of bodies 

 which act in small doses as stimulants and in 

 large doses as poisons. This property is of the 



most general nature, as Bose has shown by the 



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