of the Development of the Ovum of the Rabbit. 4-7 



Bischqffl, figs. 21 to 30. — The germ dividing and subdivi- 

 ding by means of cells, is coarsely represented as the " zerle- 

 gung" of what BischofF supposes to be the "yelk." The 

 original figures will be found in the Phil. Trans, for 1S39 

 and 1840 ; to which, and more especially to the latter volume, 

 the reader is referred for an explanation of the process by 

 which the germ thus reproduces itself, and multiplies its cells; 

 a view being there given essentially differing from the views 

 of others regarding "cells," — which latter certainlv could not 

 have explained the process. It is deserving of notice, that 

 BischofF, — though he takes some pains to show the inapplica- 

 bility of the theory of "cells" to the divisions of what he 

 calls the "yelk," — avoids mentioning my peculiar views on 

 "cells." 



Bischoff; figs. 31, 32, 35, 36, 37.— Having failed to find the 

 large cell in the mulberry-like body, BischofF also fails to dis- 

 cern its nucleus, and mistakes the cells lying around this 

 nucleus, and the cells into which the outer portion of this 

 nucleus has been resolved, for a heap of yelk-globules, re- 

 maining over in order to future use. 



Bischojffi fig. 39. — The " Fruchthof," represented in an 

 ovum of I'". I am not surprised that BischofF could describe 

 and figure this region merely as a spot — the tache cmbryon- 

 naire of Coste— consisting of nucleated cells in different degrees 

 of aggregation. At this I am not surprised, for BischofF ac- 

 knowledges having seen no ova between ±-'" and \ V} : and this 

 he calls " a small hiatus" in his observations. It is added 

 that the " Fruchthof" (tache embryonnaire) in previously 

 mentioned ova was not recognised, " but yet perhaps was pre- 

 sent, and only very difficult to find." At p. 92 it is remarked, 

 " I will not deny that it [the ' Fruchthof] is to be found in 

 ova of I'": indeed it may be traceable to the remains of the 

 yelk-globules, which were not all expended in the formation 

 of the germinal membrane." BischofF then is not prepared to 

 deny that the " Fruchthof" or tache embryonnaire may exist 

 in ova of ~". At p. 91 he confesses having seen no ova be- 

 tween j'" and I'". This, as already stated, he calls " a small [?] 

 hiatus" in his observations, which he regrets, because "Barry's 

 marvellous figures 121 — 126 relate to ova off", £"', and £'"" 

 — i. e. they relate to just that period, concerning which Bis- 

 chofF confesses he failed to make any observations. On the 

 states represented in " Barry's marvellous figures " (figs. 121, 

 &c.) it is added, " Of importance they cannot be, as subse- 

 quently nothing is found of them." Yet, after examining 

 larger ova, he admits that "perhaps there is something present 

 of an explanatory character" in smaller ones. Yes, Professor 

 BischofF, had that " small [?] hiatus " been filled up, it would 



