1883] 



MICROSCOPICAL JOURNAL. 



105 



impregnation, and then their develop- 

 ment goes on in a manner yet unknown. 



4. The testicles develop themselves 

 (luring conjugation, usually by in- 

 creasing to seed capsules, and these 

 become exchanged between the ani- 

 mals that have connection with each 

 other, in order to impregnate the 

 eggs, as the spermatozoa come out of 

 the capsules and enter the eggs. 



5. After the propagation, /. e., 

 after depositing the eggs, the animals 

 produced by the conjugation gradually 

 reconstruct their sexual organs again, 

 and live an asexually productive life, 

 /. t'., by division, yet a special mode 

 regarding the reproduction by division 

 of those animals produced by conjuga- 

 tion cannot be established. 



To these five points which state the 

 quintessence of Balbiani's conception 

 and interpretation of conjugation, I 

 desire to put in juxtaposition five 

 propositions as results of my investiga- 

 tions in 1876, those points, which 

 Halbiani, as above remarked, con- 

 firmed in all essentials. 



1. Infusoria are 7iot animals that 

 can be classed with the metazoa, they 

 contain no ovaries, no testicles, but 

 are unicellular like the rest of the 

 Protozoa, and have two kinds of cell- 

 nuclei, a so-called secondary nucleus 

 (main or nucleus proper, Balbiani's 

 ovary), and one or more primary 

 nuclei (so-called nucleoli, Balbiani's 

 testicles). 



2. The act of conjugation cannot 

 be compared with the copulation of 

 the Metazoa, but with the act of 

 fertilization, between the ovum and 

 the seminal vesicle of the same. We 

 can therefore speak here of herma- 

 phroditic plasticles in the sense of 

 Hackel, (compare p. 216 of my pam- 

 phlet, reprint.) 



3. Infusoria do not form ova during 

 or after their conjugation out of 

 the nucleus, (secondary nucleus,) so- 

 called ; what Balbiani considered to 

 be ova, are partly products of de- 

 composition of the dying secondary 

 nucleus, partly however metamorphic 

 jjroducts of the primar}' nucleus or 



nuclei which develop during their 

 conjugation. The secondary nucleus, 

 therefore, does not develop any ova, it 

 rather becomes partially or wholly an- 

 nihilated, either by dissolution or 

 elimination of its diversely metamor- 

 phosed remnants, or by a sort of de- 

 crescence of the entire secondary 

 nucleus. 



4. There are not developed any sem- 

 inal vesicles (Balbiani's "testicles,") 

 out of the primary nuclei. On the 

 contrary they pass through peculiar 

 metamorphic processes which are con- 

 nected with reproduction, in the course 

 of which there grows out from a part 

 of the primary nucleus one or more 

 bodies of the quality of the secondary 

 nucleus, which are destined to replace 

 the lost secondary nucleus, or to com- 

 bine with a remnant of the same to 

 form a new secondary nucleus. 



5. Out of the conjugation there 

 come forth animals, which, though 

 their secondary nucleus is undoubtedly 

 nf'wly formed, or increased by an 

 additional part, can be designated in 

 a certain sense as new beings. These 

 animals rejuvenated by conjugation, 

 distinguish themselves by very en- 

 ergetic growth, and rapid increase by 

 division. After their increase has 

 continued by division for a certain 

 time, the sire of the animals decrease 

 more and more, and finally there 

 arises a new period of conjugation 

 and rejuvenation. 



Now I desire to recall to the reader 

 Balbiani's words, which he applies to 

 describe the question of conjugation, 

 tweiity years ago and to-day. '" II n'y 

 a de change que quelque details ou 

 processus, mais le fond de I'interpreta- 

 tion e reste le meme, qu'il y a vingt 

 ans," and then further the classical 

 expression : " il (Biitschli) laisse le 

 phenomene de la conjugaison des 

 infusoires plusobscurqu'iln'etait avant 

 ses recherches." 



I think the reader will be astonished 

 at these remarks, just as I was, 

 when I read them. Balbiani himself 

 must be so, when he compares these 

 words of his, with those which he wrote 



