374 JVAa^ are Animals and Plants f ' 



science it is a most complicated series of changes, chemical 

 and physical — oxygenation, decomposition, the formation of 

 water, capillary attraction, etc., etc., all of which must be 

 taken together to explain by their diverse simultaneous 

 activities the apparently simple eftect. 



But not only is the existence of a diflPused ' vital force ' 

 not demonstrable, and not only do men of science yield to 

 a general tendency of human nature in imaging forth the 

 worid's activities generally, in terms of moving matter ; but 

 they very properly advocate the use of a means which 

 experience has shown them to be most efficacious for their 

 own legitimate end, which is the progress of physical science. 

 The wonderful discoveries which modem research has made, 

 have been made, not by investigating the ebb and flow of 

 an imaginary 'vital force,* but by the appHcation to the 

 study of living nature of the previously ascertained laws 

 of chemistry and physics. The discovered laws of the 

 phenomena of digestion, of respiration, of the circulation 

 of the nutritive fluids, etc., are all instances of the successful 

 appHcation of physics to the investigation of the phenomena 

 of life. To that fruitftd source alone we have also to look 

 for the remedies of the physical ills of bodily life, for the 

 perfecting of the trained skill of the physician, as weU as, 

 and no less than, that of the more obviously mechanical 

 art of surgery. 



Physical science can repose upon and appeal to nothing 

 but things evident to the senses. It is thus compelled to 

 make use of a mechanical imagination of nature, and no 

 blame can therefore attach to physicists who regard this as 

 their praMical ideal, and attend exclusively to the physical 

 forces, disr^arding that discredited figment termed 'vital 

 force.* 



Should we, then, really accept the mechanical theor}' of 

 the imiverse as an absolute truth ? and are we to r^ard 



