TIE INTELLECTUAL OBSERVER. 



MARCH, 1869. 



THE CONDITIONS OF INFUSOKIAL LIFE. 



A scientific controversy, carried on by able and assiduous ex- 

 perimenters, cannot fail to enlarge the boundaries of knowledge, 

 although it may not decisively affect opinion on the special subject 

 in dispute. This has been the case with the discussions on 

 spontaneous generation, or " heterogenesis," which have occu- 

 pied the attention of French scientific men and of the Academy 

 of Sciences for the last few years. The main question has not 

 been elucidated so as to compel the assent of both parties to the 

 same views; perhaps not a single eminent convert has been 

 made on either side, but information has been elicited of a very 

 valuable kind. Before M. Pouchet, of Eouen, came forward as 

 the champion of heterogenesis, the balance of evidence was in 

 favour of those who believe that infusorial life manifests itself 

 only when' germs are present, and other appropriate conditions 

 provided; and so the matter still stands. It must not, how- 

 ever, be imagined that the parties to the controversy do no 

 more than reiterate the old convictions. The spontaneous 

 generationists have adopted a substantially new theory, differ- 

 ing as much from the opinions of their predecessors, as the 

 speculations of Darwin differ from those of Lamarck ; while the 

 " panspermists," as M. Pouchet calls them, must feel the 

 necessity of modifying their ideas of germs. It is unwise to 

 let the dislike of a doctrine lead to the belief that it is extinct ; 

 but this feeling seems to have actuated the authors of that 

 valuable work, the " Microscopic} Dictionary," for in the second 

 edition, dated 1860, we find these words in page 312, '"''the 

 doctrine of spontaneous generation may now be said to have 

 become a matter of history •" although at that very time the 

 Comptes Rendus gave ample proof that many of the acutest 

 thinkers in France were engaged in experiments, and counter- 

 experiments, which have not yet ceased. 



It is not the intention of the writer to discuss the funda- 

 mental principles of the opposing theories ; but before giving 

 an account of M. Pouchet' s observations, which have a value 



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