THE BEGINNINGS OF LIFE. 245 



delight I found it studded with thousands of embryo 

 Paramecia^ whilst others were free and active in the 

 infusion. It was, therefore, a most significant fact 

 that they should have been met with on the very first 

 occasion that a cold maceration had been employed 1 ; 

 whilst not a single Paramecium had ever been seen before 

 in any of the many hay infusions kept in the same 

 place 2 , although several of them had even been made 

 with water whose temperature was not more than 

 i 25- 1 30 F, and which therefore was not high enough 

 to have killed any embryos that may have chanced tc 

 pre-exist in the infusion previous to its filtration. 



The maceration was at the time covered by a thick 

 pellicle, which had become brown on its upper surface, 

 Its under layers, however, were still soft and pulpy. 

 When a small portion of it was transferred to a micro- 

 scope slip, and gently compressed by the covering glass 

 so as to flatten it out into a thinner layer, the granular 

 membrane was observed to be pretty thickly studded 



1 Owing to the coldness of the weather (the daily temperature of the 

 room being scarcely above 60 F) they did not make their appearance in 

 the pellicle till more than fourteen days ; although with a daily tempera- 

 ture of 75 F they are said by M. Pouchet to begin to make their appear- 

 ance on the third or fourth day. I had examined the pellicle of my 

 maceration from time to time during the first week, but did not look at 

 it subsequently for several days not, in fact, until the day on which I 

 received M. Pouchet's letter. During the first week the pellicle had 

 become very thick and pulpy, but the weather being rather colder at 

 this time, it was principally giving birth to various kinds of Fungus- 

 germs. 



2 Beneath a bell-jar in my study. 



