Fecundation of the Ovum. 299 



took upon himself the easy task of proving to Keber that he had 

 never seen zoosperms in the interior of the Naiades^ that he 

 could not consequently have followed their development for 

 weeks, and lastly, that the tailless spermatozoid so often seen by 

 Keber occupying a transverse position in the micropyle, was 

 nothing but the inner opening of the latter. The membrane of 

 the albumen and the vitelline membrane admitted by Keber, 

 besides the cortical membrane in the Anodontce and Unios, 

 having no existence in reality, the neck-like micropyle could not 

 be a prolongation of the former ; it belongs in fact to the cortical 

 membrane itself. 



Nelson^s observations, like those of Barry and Newport, were 

 more difficult to refute ; but we need not dilate upon the objec- 

 tions raised against them by Bischoff, as the latter has since 

 recognized his error. We may however refer to the fact, that 

 Bischoff asserted that the spermatozoids which Nelson had seen 

 penetrating into the ova of Ascaris mystax were not sperma- 

 tozoids, but epithelial productions, to which he gives the name 

 of epithelial conules. These pseudospermatozoids, or epithelial 

 conules, according to him, are scattered between the papillse of 

 the mucous membrane of the oviduct, from which they are very 

 easily detached ; they are wanting, however, in the lower part of 

 the oviduct [sphincter of Bischoff), and exist under the papillse of 

 the uterus. The vagina presents neither papillae nor epithelial 

 conules. 



In conclusion, Bischoff was very harsh in the tone of his refu- 

 tation, treating the English anatomists in a somewhat patron- 

 izing style, and scarcely honouring the unfortunate Keber with 

 a few strokes of his teeth. What was the astonishment of the 

 learned world, therefore, when a few months afterwards it saw 

 a fresh publication of the embryologist of Giessen with the title 

 — " Confirmation of the penetration of the spermatozoid into 

 the ovum, discovered by Newport in the Batrachia, and by 

 Barry in the Rabbit*." In this work, Bischoff says, with a 

 rather solemn tone, "I have repeated Newport's observations 

 and hasten to state that I have confirmed them in every respect, 

 and that there is no longer any doubt that the spermatozoids 

 actually penetrate into the egg of the Frog. After convincing 

 myself of this fact, I again took up the study of the ovules of the 

 Rabbit, and I do not hesitate in stating that I was wrong in 

 contradicting Barry, and that in this case also there remains no 

 doubt that spermatozoids really penetrate into the ova of these 



* Bestatigung des von Newport bei den Batrachiern und Barry bei 

 den Kaninchen behaupteten Eindringens der Spermatozoiden in das Ei. 

 Giessen^ 1854. 



