to M. Coste' s Memoir. 195 



dition of my first marsupial ovum, and after having found it 

 to differ from the ova of the placental Mammalia in the ab- 

 sence of the allantois, to trace the developement of the bird 

 up to the period when the allantois first buds out, and I in- 

 troduced a figure of the embryo of the goose at this period, in 

 order to contrast its advanced condition of developement, as 

 compared with the placental mammiferous embryo at the cor- 

 responding stage of the developement of the allantois, and to 

 shew the degree of correspondence which thus existed between 

 the oviparous and marsupial embryo. 



I come lastly to consider the evidence which M. Coste has 

 adduced to prove that the uterine product of the kangaroo 

 submitted to him by me, was an entire ovum, which had not 

 previously undergone dissection. I have already asserted 

 that this ovum had been dissected by me, — so far as the ex- 

 posure and discovery of the allantois and umbilical -vesicle 

 were concerned, some weeks before M. Coste saw these parts. 



M. Gerbe, in his letter to the Academy, states that I spoke 

 of the preparation in question to M. Coste, as " un produit 

 uterin de kangaroo, qu'il n'avait point encore eu le temps 

 d'examiner." I assert that I informed M. Coste distinctly, with 

 reference to the preparation in question, that I had not then 

 had time to give a description of it. 



I comprehend perfectly the delicate position in which the 

 commission is placed by these contradictory statements. 



I could not have made a more explicit statement, even had 

 it been possible for me to have entertained the idea that the 

 preparation I was about to exhibit to M. Coste, could ever 

 have been mistaken for an undissected ovum. 



M. Coste however adduces M. Gerbe's description of the 

 state of the ovum, when it was first submitted to their view. 

 This part of M. Gerbe's testimony I accept ; the truth of his 

 description I acknowledge. I am willing that my case should 

 rest upon it, — upon this evidence adduced by M. Coste. And 

 now the commission and every impartial physiologist possess 

 ground for forming their judgment as to the truth of M. Coste' s 

 assertion, that he was the first who dissected the ovum in ques- 

 tion, independently of speculations as to the value of his or 

 my word. 



M. Gerbe's description is as follows. "Ce que j'ai vu, et 

 ce que je puis afnrmer en toute assurance, c'est que rien n'in- 

 diquait que cet ceuf eut ete disseque." This would have been 

 an unfortunate statement for me, if he had omitted to describe 

 what he did see. But he proceeds to say ; — " Le foetus seule- 

 ment etait isole de ses membranes, mais celle-ci etaient ex- 

 cessivement pelotonnees ensemble. L' amnios meme etait tres- 



