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



Bischoff, p. 86. — I never added any chemical reagent to 

 ova of the size of Bischoff's ovum figs. 29 and 30. He makes 

 it appear as if the addition of a reagent had been my practice. 



Bischoff, p. 10. — Professor Bischoff has no authority what- 

 ever for stating that I appear to have used for the most part 

 a magnifying power of 100 diameters. The objects were for 

 the most part delineated as magnified 100 diameters; but it 

 surely does not follow that no higher magnifying power was 

 used in the examination. The powers employed varied, from 

 less than 100 to 800. 



Bischoff, p. 89. — States that Barry has not attempted to ex- 

 plain the appearance of the ovum in his fig. 119 (my " Second 

 Series"); which, therefore, and because he (Bischoff) saw 

 such a condition of the ovum only once, he thinks was an 

 aborted ovum. — The reader will find whether I failed to ex- 

 plain this appearance, on referring to my " Second Series" of 

 Researches, /. c, § 201, which paragraph is entitled "nine- 

 teenth stage of development — hollow network in the ovum." 

 This state of the ovum then it appears was seen by Bischoff' 

 "only once!" (See my figs. 120, 121, 152, for later stages.) 



Bischoff, p. 3. — Says that the ovulum is "covered on all 

 sides by the cells of the membrana granulosa," and that these 

 cells, being more densely aggregated around the ovulum, form 

 an opake ring. Yet this, though covering the ovulum " on 

 all sides," he calls a disc. Had Bischoff obtained a suite of 

 stages, he would have seen it sharply circumscribed, and per- 

 fectly spherical in form. 



Bischoff, p. 30. — " In this state of things observation needs 

 to take but one step more, i.e. only to see the spermatic 

 threads [spermatozoa] penetrate the ovum, or to find them 

 there : a probability would thus become a certainty." — p. 32. 

 " But I have never been able to convince myself that one of 

 these spermatic threads [spermatozoa] was in the interior of 

 the ovum." Professor Bischoff may now be informed that 

 this has at last been done (see " Proceedings of the Royal So- 

 ciety, Dec. 8, 1842"); spermatozoa within the "zona pellu- 

 cida," i. e. certainly in the interior of the ovum, having been 

 found by myself, and shown to, and acknowledged by, others, 

 — among whom was Professor Owen, who, in a note 1 have 

 received from him, states that he "can confidently attest the 

 reality of the spermatozoa." [Since the above was written, I 

 have confirmed my first observation by a second.] 



Bischoff, p. 38. — Acknowledges having seen the germinal 

 spot to appear not quite round, but like a flattened vesicle, 

 and presenting a "pellucid ring." And though in 1839 he 



