ON THE VITALISTIC VIEW OF NATLllE. 443 



The modern theories of the cell, of metabolism, and 

 selection, have also greatly influenced and modified our 

 conceptions concerning the last itnd nmsl imiHirlaiil pro- 

 perty of all living matter — viz., that it is self-reproductive. 

 Older text -books on i)liysiology treated of the great -is- 

 problem of generation — i.e., the origin of a new individual ^''"'- 

 — as a phenomenon of organised life which stood quite 

 isolated ; and although the sexual difference in plants 

 and animals had early led to certain analogies, to similar 

 terminology, and to vague inferences, the mysterious 

 phenomena of generation, and especially of sexual genera- 

 tion, were not brought into line with the general pro- 

 perties of all living matter till about fifty jjears ago. 

 Even Johannes Miiller in his great text - book on 

 Physiology, which takes a much wider view of the sub- 

 ject than any work before it, treats of the reproduction 

 of tissues and of generation in (juite separate, seem- 

 ingly disconnected, parts of his work. Into this un- 

 certainty only little light was thrown l)y the original 

 prcjpounders of the Cellular theory, who, misled by the 

 supposed analogy of cells and crystals, imagined that 

 cells originated out of the surrounding cell sap, as 

 crystals solidify out of the solution or mother liquor. 

 Correcter views were gradually elaborated by botanists. 

 Mohl emphasised the important part which protoplasm 

 plays in the formation of cells. Niigeli established the 

 process of intussusception as against external accretion ; 

 anatomists like Max Schulze and Briicke joined hands, 



pos.sible express the doctrine wliicli 

 Dr Gaskell and Prof. Hering have 

 embodied in word.s which have now 

 become fainiliar to every student. 

 The words in question — ' anabolism,' 



whiclr, being interpreted, means 

 winding-up, and 'catabolism,' run- 

 ning down — are the creation of Dr 

 Gaskell." 



