THE GENESIS OF LIFE. 165 



or " equivocal generation," was replaced by the name 

 " Heterogeny," or " Heterogenesis ; " whilst in these latter 

 days, disciples of Redi and Spallanzani are said to support 

 " Biogenesis," against the theory of " Abiogenesis," or that 

 which maintains that living beings may and do, under certain 

 -circumstances, originate from non-living matter. 



The statement that no branch of science is independent 

 of its neighbour-departments, and that the growth and pro- 

 gress of one science in reality means the advance of the 

 whole scientific coterie, receives an apt illustration from those 

 phases of the present subject which succeeded the experi- 

 mentation of Spallanzani. From amongst the myths of 

 alchemy, the science of true chemistry was, at the date of 

 Spallanzani's experiments, just beginning to be evolved ; and 

 shortly after his day, men began to know something definite 

 regarding the composition of matter and respecting the laws 

 in virtue of which elements combined to form the compound 

 substances met with in the world at large. It has been well 

 said that the science of chemistry was founded on the dis- 

 covery of oxygen and its properties ; and it so happened 

 that through the investigation of the relations borne by 

 oxygen to living beings, the subject of " biogenesis " versus 

 " spontaneous generation " received an accession of new life, 

 and the old controversy was, in consequence, revived with 

 renewed vigour. Chemical alarmists subjected Spallanzani's 

 work to scrutiny on the ground that they deemed it possible 

 for the fluids in the flasks to have been altered by the applied 

 heat so as to utterly prevent the development therefrom of 

 living beings. The chemical alteration of the liquids, in 

 other words, was a result which had not been bargained 

 for by Spallanzani or his contemporaries, and was, moreover, 

 a condition which, provided its existence could be proved, 

 would unquestionably operate to falsify the results of experi- 

 ments. " If you literally kill (through chemical alteration 

 and change) the organic molecules in the infusion," said the 

 supporters of Needham and Buffon, "of course you will 

 obtain a negative result ; but your conditions of experimen- 



