CHEMICAL CHANGES. 67 



vital is constantly applied to actions which, for the last 

 fifty years, have been admitted to be mechanical and 

 chemical, and the confusion with regard to the meaning 

 of the word has been further increased by the assertion 

 that mechanical and chemical actions are the only actions, 

 that are to be called vital. Some philosophers have 

 indeed arrived at the conclusion that in truth there are 

 no vital as distinguished from physical and chemical actions. 

 Further, it has been held that as we can imitate osmose, 

 oxidize certain substances and produce in the laboratory 

 compounds like those formed in the body, we may pro- 

 phesy that all other actions occurring in living beings will 

 eventually be imitated. But it would be as reasonable to 

 maintain that because we can now produce urea we shall 

 by and by be able to form a hair or develop an eye out of 

 the contents of a crucible, or that as we can build up by syn- 

 thesis very complex organic compounds, ere long we shall 

 be able to make a brain cell which will form ideas. Because 

 we can make many products like those resulting from the 

 disintegration of tissues, does it therefore follow that in the 

 time to come we shall be able to develop an embryo by 

 the admixture of two kinds of albuminous fluids prepared 

 artificially? As oxygen and hydrogen can be made to 

 combine by the contact of platinum, therefore it is said 

 certain combinations of living particles are also examples 

 of catalytic action. Because many actions have been attri- 

 buted to vitality which are unquestionably physical and 

 chemical, therefore all actions which are now regarded as 

 vital will ultimately be proved to be physical. Those who 

 argue in this way fail to perceive that they are dealing with 



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