86 The Science of Life. 



the organism a self-stoking and a self-repairing engine, 

 both notable qualities, but there is an even deeper con- 

 trast, which has been stated by Dr. Joly in a remark- 

 able paper entitled "The Abundance of Life" (Proc. 

 Roy. Dublin Soc., 1890): "While the transfer of 

 energy into any inanimate material system is attended 

 by effects retardative to the transfer and conducive to 

 dissipation, the transfer of energy into any animate 

 material system is attended by effects conducive to the 

 transfer and retardative of dissipation". Following 

 probably from this we have the great contrast, which 

 admits of no denial, that however perfect the inanimate 

 engine may be in its work and longevity, it never gives 

 rise to other engines, while it is characteristic of the 

 organism that it is reproductive. 



Over and over again in the history of biology the 

 doctrine of a special vital force has arisen, held sway 

 "Vital for a time, and then disappeared. It arises 

 Force." as a reaction from the false simplicity of 

 premature solutions, or as a despairing retreat in the 

 face of baffling problems, or as the result of misunder- 

 standing the real aim of science. 



The doctrine is an old one, for even if we ignore the 

 speculations of the ancients, it must date at least from 

 Paracelsus and Van Helmont. As it has naturally 

 taken very different forms in different generations, the 

 word "vitalism", so often used, has little definite 

 meaning. There is a sense in which no modern physi- 

 ologist is a vitalist, since none rejects physico-chemical 

 interpretations as the early French vitalists did ; there 

 is a sense in which all modern physiologists are vitalists, 

 since none pretends to know the secret of that par- 

 ticular synthesis which even the simplest of organisms 

 illustrates. 



The phrase "vital force" may be used as a general 

 expression for the energies resident in living matter, 

 and may serve to suggest that we do not at present 

 understand them, or how they are related in the unity 

 of the organism. But the phrase was originally used 

 to denote a " hyper- mechanical force", a mystical 

 power, resident in living creatures, and quite different 



