292 M. E. Claparede on the Theory of the 



but a reproduction of Harvey's * ideas, when he compared the 

 action of the spermatozoids upon the ovum to that of the mag- 

 net upon iron, or when, with Osiander and Treviranus, he called 

 it a contagion. 



The reign of the old theories appeared to be repudiated for 

 ever, and it was scarcely expected that they would soon have 

 raised their heads again to claim the attention of true observers, 

 no longer taking the title of theorieSy but rather that oi facts, 

 and demanding no other judges than eyes and a sound intellect. 

 This is nevertheless what took place. As early as 1840, a distin- 

 guished English observer. Dr. Barry f, in a memoir on the em- 

 bryogeny of the Rabbit, devoted a chapter to the fecundation of 

 the ovum, and asserted that he had seen this take place under 

 his eyes. According to him the germinal vesicle of the ovum of 

 the Rabbit neither dissolves nor bursts, as was generally sup- 

 posed ; but at a period preceding that of fecundation it becomes 

 filled with cells, which render it opake, and then proceeds in 

 the direction of the periphery, towards the zona pellucida [trans- 

 parent membrane). The latter presents an attenuation or an 

 orifice at the point approached by the vesicle. This, at least, is 

 what Barry asserts that he has seen several times in perfectly 

 ripe ovules, even ante coitum. The form of the orifice in 

 question was sometimes such as to suggest the idea of a rent or 

 cleft in the membrane; in other cases it appeared as though 

 there had bee a a previous attenuation of the membrane. Sub- 

 sequently J Dr. Barry again described this phsenomenon in 

 greater detail. With him the nucleolus of the germinal spot is 

 a peculiar substance which he calls the hyaline. In this hyaline 

 resides the force (the explanation again leaves nothing to be 

 desired !) which drives the vesicle towards the zona pellucida. 

 When the germinal vesicle comes in contact with the membrane 

 of the egg it bursts, and at the same time an opening is formed 

 in the latter [zona pellucida) . All this is the work of this hya- 

 linic energy ! However, an opening, whether formed or not by 

 the action of the hyaline, was observed in 1840 by Barry in the 

 ovum of the Rabbit, and on one occasion he even perceived in 

 this aperture an object "much resembling a spermatozoon.^' All 

 these phajnomena of course take place before the formation of 

 the chorion, that is to say in the ovary, or in the uppermost part 

 of the oviduct. Two or three years afterwards Barry § announced 

 positively that he had seen not only an object " much resembling 

 a spermatozoon," but actually true zoosperms in the ova of 



* Exercit. de Generatione Anim. 1651. 



t Phil. Trans. 1840. 



: Muller's Archiv, 1851. 



§ Phil. Trans. 1843. 



