404 SCIENTIFIC THOUGHT. 



question was definitely settled and the road quite 

 clear for research. To those — and they comprised the 

 second class of thinkers referred to above — who were 

 unwilling or unable to follow Lotze and Du Bois- 

 Eeymond into the details of their criticism of the 

 illogical conception of force as employed in the term 

 " vital force," but who looked at the great facts of 

 economy, design, and recurrent order which are exhibited 

 in the living creation, these criticisms had little that 

 was convincing. If the term " vital force " was illogical, 

 some other term such as " vital principle " might be 

 substituted. The enormous difference between the 

 phenomena of living and of dead matter remained and 

 impressed itself on them. Liebig, and many naturalists 

 in France and Germany, had approached the study of 

 nature from the practical side. Their methods were not 

 mathematical but rather experimental, and very fre- 

 quently not limited to the laboratory and dissecting-room, 

 but carried out in the workshop of nature itself. In 

 spite of his successful attempts to establish clearer views 

 regarding the economic processes of living nature and 

 the application of chemical analysis, Liebig ^ to the end 



the mystery which attaches to i be studied liy every one who desires 

 all beginnings as well as to the to be at home in the ancient and 



great transitions in the ascending 

 scale of natural phenomena being 

 further emphasised and forcibly 

 driven home in the last - named 



modern literature of the f^ubject. 

 The position of the author has 

 been many times criticised. See, 

 inter (dill, Kaufmann, ' Die Meta- 



address, which, as has been said, | physik in der modernen Biologic ' 



bears the title "The Seven Enig- ! (Jena, lS9i], passim. 



mas. " The three deliverances of Du i ^ Lord Kelvin in his essay " On the 



Bois-Reymond, together with the | Dissipation of Energy " (reprinted 



copious notes and references which 

 he gives in the latest reprint, 

 serve as a very good and lucid 

 exposition of the inherent diffi- 



in ' Popular Lectures,' &c., vol. iii. 

 p. 464) has the following interesting 

 note: "The influence of animal or 

 vegetable life on matter is infinitely 



cuities of the problem, and should . beyond the range of any scientific 



