8o LIFE. 



Neither should changes which are admitted to be me- 

 chanical and chemical, when they occur in the laboratory, be 

 called vital, merely because they take place in a living 

 organism. It is the nature of the change alone which 

 determines its vital or non-vital character. But the term 

 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 put 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 



