30 8 THE BEGINNINGS OF LIFE. 



tion of all those complex molecular movements which 

 go on within, and essentially constitute the life of the 

 ultimate constituents of their several tissues. And as 

 the essentially vital changes (or molecular movements) 

 diminish, so do the ultimate molecules of the living 

 tissues begin to undergo rearrangements and decom- 

 positions. 



We have already endeavoured to show, by cogent 

 experimental evidence, that when organic matter decays 

 or putrefies, a double process of composition and decom- 

 position invariably occurs: the complex organic sub- 

 stances partly break up into simpler binary compounds, 

 during which the previously locked up forces become 

 instrumental in bringing about new synthetic changes 

 among other constituents of the organic matter; and 

 the new products appear as specks of living matter, 

 which gradually grow into Bacteria^ Torul£^ or other 

 simplest forms of life. ^ Vital ' processes thus lapse into 

 ordinary chemical processes ; and thus in turn do these 

 chemical processes again give birth to "^ vital' com- 

 binations. We now hav2 to refer to this and other 

 modes by which independent living units may arise in 

 the bodies of dead or living organisms. 



Whilst it may be possible for heterogenetic changes 

 to take place in some part of the body, even of 

 a healthy animal, provided the intimate vital move- 

 ments and changes in that particular part are much 

 altered, either accidentally or by the effects of local 

 disease ; it becomes much more common for such 



