46 Dr. M. Barry on Prof. Bischoff's History 



Bischqff] p. 87. — After altogether denying the existence of 

 cells hitherto, — now suddenly admits them. 



Bischqffi, fig. 42 G. — " Star-shaped and nucleated cells often 

 uniting with one another." " The situation and relation of 

 these cells between the cell-layers forming the animal and ve- 

 getative laminae, make it possible that they belong to that 

 which becomes what certainly manifests itself as the vascular 

 lamina, and that they indicate the commencement of the ves- 

 sels of the area vasculosa." Compare this figure of Bischoff's 

 — fig. 42 G, — and the description now quoted, with fig. 132 

 in my "Second Series" (I.e., 1839), and with the description 

 I there gave of it, viz. " Fig. 132. A portion of the network 

 of which the subsequently vascular lamina of the umbilical 

 vesicle consists" (/. C, p. 379). My figs. 120, 121 and 150 

 are mentioned in that same paper, as representing the succeed- 

 ing stages, — fig. 150 being thus described : "Vesicles of the 

 outer and subsequently vascular lamina of the umbilical ve- 

 sicle." With these passages before his eyes, and at the same 

 time comparing my fig. 120 with his fig. 41 g, how could 

 Professor BischofF coolly say that, since the cells in his fig. 

 41 g presented precisely such an appearance as that which 

 Schwann had given of the first development of the vessels in 

 the Bird's egg, the thought had occurred to Mm ("so gerieth 

 ich auf den Gedanken") whether at this early period there 

 might not exist a cell-layer in which the future vascular lamina 

 should have its origin ! (See his pp. 96, 97.) 



BiscJutff] p. 95. — Boasts of being able to demonstrate two 

 laminae of the "germinal membrane" in the Rabbit's ovum 

 measuring If" to 2'", and forgets that this had previously 

 been shown in a rabbit's ovum of less than i'"; and that 

 ("Second Series," I.e. §206, figs. 120, 121 A) the inner 

 layer, or vascular lamina, as I called it, had been stated to 

 present a lamina internal to it. In 1839 I remarked (" Second 

 Series," I.e. § 167), "there is no fixed relation between the 

 size of the entire ovum, and the degree of development of its 

 most essential part;" in proof of which I referred to my fig. 

 1^4, — and the variable period at which villi begin to appear 

 on the chorion afforded another instance. This irregularity 

 should be borne in mind. It probably explains how it is that 

 the same appearance should present itself in an ovum of 3'" 

 (Bischoff's fig. 42 G), and in one of §■'" (my fig. 120) ; being 

 incipient also in an ovum of i'" (my figs. 1 19, 132). It should 

 be recollected that Bischoff did not always find it in his more 

 advanced ova (p. 97) ; and that, as above stated, I have met 

 with ova of 2'", apparently not more advanced in reference to 

 the network, than the ovum in my fig. 119 — which measured 

 only £'". 



