DEATH 283 



suited to the particular Infusorian under observa- 

 tion, had in each case to be determined. No less 

 than twenty different species were experimented 

 upon, and the whole research, both as regards 

 the extreme patience necessary for its proper 

 conduct, and the great importance of the results 

 obtained, justly ranks among the most famous of 

 its kind. 



The general results of Maupas' investigation, 

 which deserve to be followed in detail by all micro- 

 scopists, were to this effect : In conjugation the 

 paranucleus of each of the conjugating individuals 

 acts as a hermaphrodite sexual element : it under- 

 goes successive divisions, and parts are extruded 

 and lost completely. The remaining parts of each 

 paranucleus become differentiated into male and 

 female pronuclei ; interchange of the male pronuclei 

 takes place between the conjugating individuals, 

 and the male pronuclei then fuse with the female 

 pronuclei of the individuals to which they have 

 been transferred. The entire nuclear apparatus of 

 each of the conjugating individuals is now recon- 

 stituted, and the two Infusoria separate and 

 become independent once more. The purpose of 

 conjugation appears to be to stimulate the asexual 

 act of fission. Individuals which previous to con- 

 jugation showed no tendency to divide, begin to 

 do so actively as soon as conjugation has been 

 completed. In order however for conjugation to 

 be effective, Maupas finds that it must take place 

 between individuals which are not closely related 

 to each other. Members of the same family show 



