Fecundation of t lie Oram. 29.") 



These three discoveries of the penetration of the spermatozoids 

 into the ovum were soon to be followed by several others. In 

 fact, we are arrivinj^ at the moment when this new theory, or 

 rather, this resurrection of antiquated ideas now founded upon 

 observation, was to excite general interest, and bring into the 

 arena all the distinguished names of which physiology can 

 boast. 



Shortly after Newport's discovery, there appeared at Konigs- 

 bcrg a work by a ^I. Keber* of Intersburg, — a work which 

 came forth with the pretension that it would change the face of 

 science, and convulse with astonishment, not only Konigsberg, 

 not only Germany or Europe, but the whole world. The work 

 was published in two languages, German and Latin, in order 

 that no one should have an excuse for want of knowledge of the 

 new doctrine, for ignorance of the truth. " I shall prove by 

 innumerable observations," is the pompous announcement of 

 Keber in his preface, " that no animal fecundation takes place but 

 when the spermatozoids penetrate into the ovum, divide in the 

 vitellus and form the nuclei of the cells of the new organism, . . . 

 I feel all the weight of this bold assertion ; I know that I am 

 about by this means to place myself in opposition to the Cory- 

 phaei of science, and that more than one, offended at hearing 

 such an absurdity, will throw this work aside contemptuously, 

 without reading it, or perhaps at the utmost, will grant it a 

 place in the series of scientific curiosities. But I have carefully 

 and conscientiously convinced myself of the truth of my as- 

 sertions, upon more than 2000 eggs," &c. Exclaiming, with 

 Aristotle, that one must have more confidence in one's own eyes 

 than in the opinions of others, Keber proceeds, without disturb- 

 ing himself about the objections which may be raised against 

 him, or dreaming that Aristotle spoke of the eyes of reason and 

 not of those of the imagination. 



But let us pass to details, and first of all, to the phajnomena 

 which Keber pretends to have obsei'ved in the Naiadece {Ano- 

 donta, Unio). According to him, the ovum in these Mollusca is 

 not enveloped simply in the cortical membrane {Schalenhaut of 

 Baer) ; but within this there are two others, — the membrane of 

 the albumen and the vitelline membrane, the former separating 

 the albumen from the cortical membrane, the second from the 

 vitellus. The young ova present a csecal prolongation, which 

 arises from the membrane of the albumen and, piercing the cor- 

 tical membrane, forms a projection externally. In some cases a 

 tine membrane is perceptible uniting this process with the ger- 



* Ueber den Eintritt der Samenzellen in das Ei, ein Beitrag zur Physio- 

 logic der Zeugung. 1853. 



