28 THE ACTIVE FORCES OF LIVING ORGANISMS 



It is not easy to understand how a drop or two of such 

 a poison as prussic acid (HON) can kill as it does, 

 unless it be that the absence of any oxygen, and the 

 presence in it of hydrogen, carbon and nitrogen, cause 

 a note of arrested oxidation to be struck even more 

 pronounced than is the case with strychnine. The 

 fact that prussic acid, when produced in the course 

 of nature, is found hidden away in the kernel of 

 a hard peach-stone certainly suggests a state of 

 diminished or arrested oxidation. 

 kf'Icai an- jDjfugs are sometimes said to be physiologically 

 tagonism. antagonistic which are not really so in their mode of 

 action, or are so only in a limited and partial manner. 

 Thus strychnine (C21H22N2O2) is spoken of as the 

 physiological antagonist of physostigmine (C15H21N3O.2), 

 and may be used as an antidote in poisoning by that 

 drug. Yet the action of the two is in some important 

 respects similar : both produce constricting effects, 

 and are used in constipation. If we look at the matter 

 from the dynamic point of view, and consider the 

 molecules of our nerve-cells as vibrating in a given 

 manner according to the dynamic influence of their 

 chemical surroundings or environment, we shall at 

 once understand that a slight change in the latter 

 might suffice to alter the mode of vibration, or, in 

 other words, produce a different and apparently 

 antagonistic physiological effect. 

 Action In estimating the physiological effect of any drug, 



BiD-d r6- 



action. both its action and reaction must naturally be taken 

 into account, and since all drugs act by influencing 



