244 



THE BEGINNINGS OF LIFE. 



1 



I have also myself, quite recently, watched with the 

 greatest interest all the stages of this process, which 

 terminated in the evolution of fine specimens of 

 Parameaa^ and am most pleased, to be able to bear 

 my testimony to the general accuracy of M. Pouchet's 

 description. Up to this period I had never seen 



a single Paramecium or other 



specimen 



of the larger 



ciliated Infusoria in any of my hay infusions — these 

 having all been prepared either with warm or with hot 

 water. But about ten days previously, on re-reading 

 M. Pouchet's description of the mode of evolution of 

 these organisms, it struck me that I had failed to see 

 these phenomena owing to my never having made any 

 infusions with cold water. I therefore at once prepared 



M - 



such a maceration, and two or three days afterwards 

 wrote to M. Pouchet on the subject. In the reply which 

 he was kind enough to address to me he said : 

 *^ Jamais, jamais vous ne renconterez utz seul infusoire 

 cilie dans une experience faite a I'eau chaude. . . * . II 

 faut pour cela operer sur des macerations faites a froid^ 

 alors vous obtiendrez fac ilement la phenomene de 

 developpement des oeufs spontanes des Paramecies, dans 



les membranes proligeres qui se seront formees d'abord^" 



I received 



' On the evening of the day on which 



this letter I again examined the thick pellicle which 

 had formed on the maceration of hay, and much to my 



4 * - 



L 



^ M. Poucliet has been in the habit of using one part by weight of 

 ordinary dry hay to about forty parts of water, and of letting the mace- 

 ration stand for two or three hours before filteririg off the clear liquid. 



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