146 Life and Death, Heredity and Evolution 



this theory had been based amounted to nothing. Next he 

 sets forth that in his own records of fissions in different in- 

 fusoria, beginning in a number of cases with animals that 

 had just conjugated, there is no indication of a greater 

 rate of fission after conjugation. He says of the fis- 

 sions : 



"They succeed one another uniformly, modified only by 

 the changes of temperature. I did not remain content with 

 this one experiment. I isolated other ex-con jugants of 

 Stylonycliia pugtulata, of Onychodromus grandis, of 

 Euplotes patella, of Paramecium aurelia, of Leucophrys 

 patula. I followed day by day the successive generations of 

 their descendants, during periods of from fifteen days to two 

 months. In none of these species did I see any difference in 

 the succession of fissions. Whether they had conjugated 

 lately or a long time ago, all the individuals acted in the 

 same way" (1888, p. 255-256). 



Maupas sums up the matter in a later paper as follows: 



"I have asserted, besides, that this power of multiplica- 

 tion is maintained regularly and uniformly during the entire 

 life cycle ; that there is no gradual weakening of this power 

 from the first generation after conjugation up to the re- 

 turn of a new period of maturity. In other words, I deny 

 that the infusoria after conjugation have a more energetic 

 reproduction than they have at a later period" (1889, p. 

 504). 



Certainly this is sufficiently explicit not to be misunder- 

 stood ! It is because Maupas' papers, with their hundreds of 

 pages of text filled with observational and experimental de- 

 tails, make hard reading, that it is possible for mistaken 

 ideas of his results to become prevalent. 



Richard Hertwig (1889) found in his experiment, to his 

 surprise (as will anyone that tries it), not only that the 



