206 Dr Barry on Fissiparous Generation. 



corpuscle, like the germinal vesicle, is also propagated by 

 self-division of its nucleus. 



2. The same mode of propagation — namely, by means of 

 parent cells, self-division of the nucleus for this purpose, and 

 an orifice in the centre of the nucleus — so far as my observa- 

 tions have extended, are common to cells in general. So 

 that the Harveyan dictum — Omne vivum ex ovo, may be 

 applicable to the very cells of which an organism is com- 

 posed. 



3. Professor Ehrenberg is of opinion, that reproduction by 

 self-division necessarily produces in the offspring similarity to 

 the progenitors. This remark has reference to some of the 

 Infusoria. Now, if what Ehrenberg said of self-division, as 

 occurring in the entire organism, be just, I think it may, to 

 a certain extent, apply to the individual cells and nuclei of 

 which the organism is composed ; for, as I have already 

 stated, cells are propagated by self division of their nuclei. 



4. The ovum is fecundated by the introduction of a sub- 

 stance into the centre of the^nucleus of the germinal vesicle, 

 or original parent cell, which then gives origin to two young 

 cells. As it may be presumed that each of these young cells 

 is endowed with qualities resulting from the fecundation of 

 the parent cell, what I wish to be understood as suggesting 

 is, that such endowment of the young cells may be referred 

 to self-division. '^ This division, however, as we saw, does not 

 consist in simple separation, but is effected by a process ela- 

 borate in the extreme. The parent nucleus gives origin to 

 many cells, and these to a great number of minuter cells, all 

 of which disappear by entering into the formation of the two 

 young persistent cells. The process seems to be one of assi- 

 milat\on^ on which depends the re-appearance of the qualities 

 of both parents in the offspring. 



5. Now, it is deserving of notice, in the first place, that this 

 same elaborate process of assimilation is seen to attend the 

 reproduction of cells in general, so far as their interior can be 



* It is curious, that the original position of the young nuclei is sometimes 

 seen to be such as to induce the belief that the orijicQ itself of the i>arent nucleus 

 has undergone division. (See Phil. Trans., 1842, PI. X , fig. 134.) 



