158 Discovery of the Allantois in the Kangaroo. 



fessor Owen, as appearing to be one of words, rather than 

 of things. " Comme sur ce point la discussion parait plu- 

 tot porter sur les mots que sur les choses." Doubtless it 

 would be to the interest of the French embryologist, that 

 the Academy should see the propriety of relieving him from 

 the rather awkward position in which he is placed, by a- 

 dopting this highly ingenious suggestion ; but as the letter 

 of Professor Owen to M. Arago has been published on the 

 continent, as well as in this country, it will require no or- 

 dinary share of sagacity, on the part of M. Coste, to palm 

 upon the French savans, a view so palpably irreconcileable 

 with the statements made in that communication. 



M. Coste's description of the chorion, is, that it was 

 blended with the umbilical vesicle; — "le chorion etait con- 

 fondu avec la vesicule ombilicale." Now, Professor Owen 

 states, that prior to his shewing M. Coste the foetus, with 

 the appended allantois, he had removed the chorion, and 

 that he did not exhibit this membrane to M. Coste. The 

 real condition of the chorion we subsequently find thus de- 

 scribed by Professor Owen, in the Proceedings of the Zo- 

 ological Society, for August, 1837. 



" The chorion, which enveloped and concealed the foetus, 

 was a sac of considerable capacity, exceeding probably by ten 

 times the bulk of the foetus and its immediate appendages, 

 and adapted to the smaller cavity of the uterus, by innumera- 

 ble folds and wrinkles. It did not adhere, at any part of its 

 circumference, to the uterus, but presented a most interesting 

 modification, not observed in the previous dissection of the 

 kangaroo's impregnated uterus, viz. that it was in part orga- 

 nised by the extension of the omphalo-mesenteric vessels up- 

 on it, from the adherent umbilical sac." 



Now no misapprehension of terms can be urged, as expla- 

 natory of the fact of these two statements being so completely 

 opposed to each other, respecting the condition of the chori- 

 on. The possession of this membrane, and the consequent 

 ability to produce it, presents us with an unquestionable gua- 

 rantee for the correctness of the history of its relations to the 

 foetus, as recorded by Professor Owen. Hence we must at- 

 tribute the description of M. Coste, to his imagination; and 

 may we not assume that this faculty was called into such ac- 

 tive operation in the one case, at the expense of memory in 

 the other, as the only satisfactory explanation of the belief 

 entertained by M. Coste, that instead of Professor Owen hav- 

 ing discovered the allantois, and imparted the fact of its exist- 

 ence to his visitor, he, M. Coste, had detected the allantois, 

 and communicated the discovery to Professor Owen. 



