348 SVDKEY J. HICKSON. 



insensate^ helpless, defenceless syzyg-y would remain so long 

 if there were nothing else of essential importance done but 

 the interchange of germ nuclei. The fact suggests that 

 there is during the process some interchange of the molecules 

 of the cytoplasm, and, indeed, that the interchange or mixing 

 of the molecules is thorough, and not partial or local in 

 character. If there is during conjugation an interchange of 

 the molecules of the cytoplasm such as has been suggested, 

 it is probable that some protoplasmic streaming movement 

 would be noticed between the two individuals. The observa- 

 tions on the changes or movements of the cytoplasm during 

 the process are, however, very limited. Maupas observed that 

 numerous granules (zooamylnm) appear in the cytoplasm 

 during the conjugation of certain Ciliata, which he supposed 

 to be connected in some way with the active metabolism that 

 is going on ; but I cannot find in his writings any reference 

 to a streaming movement taking place between the two 

 individuals. But Maupas, like Biitschli and many others,^ it 

 must be remembered, regarded the micronuclear phenomena 

 as the only essential jjhenomena of the process, and did not 

 expect to find any such How of cytoplasm. 



In Dendrocometes a flow of cytoplasm between the two 

 conjugates does certainly take place. This was observed by 

 Plate and is confirmed by my own observations. Sand (23, 

 p. 100) goes so tar as to say that conjugation is essentially a 

 process of plastogamy, and that there is not the least mixing 

 of the nucleoplasm of the two individuals. But Sand's view 

 is, I believe, as far wrong in the one extreme as the older view 

 is in the other. 



Whether a similar streaming movement of the cytoplasm 

 between the conjugates can actually be observed in the 

 group of the Ciliata or not, is a question upon which I have 

 no evidence to offer. But whether it can or cannot be 

 observed under the microscope, the intimate contact of the 

 two cytoplasms renders an invisible interchange of molecules 



' Dehii^e ami Herouard say, " Les plienoiiieues iuterieurs de la coiijugaison 

 sont sufiTOUT aucleaires." 



