192 Professor Owen's Reply 



the umbilical arteries especially pointed out at c c, jig. 8, pi. 

 vii. in a very young mammary (which M. Coste translates u- 

 terine) foetus of a kangaroo, I leave the Academy to judge of 

 the candour with which the criticisms of M. Coste have been 

 penned. 



The same spirit which dictated the criticism which I have 

 just refuted pervades the succeeding paragraphs in M. Coste's 

 ' Reponse,' in which he insinuates that I had overlooked the 

 allantois in my first dissection, and dwells on the difficulties 

 he had to overcome in detecting it in my second. 



" II nous a fallu derouler les membranes afin de pouvoir 

 distinguer les unes des autres ; nous ajouterons que l'allan- 

 toi'de etait tellement comprimee et se confondait si bien a- 

 vec les parois de la vesicule ombilicale, avec laquelle elle 

 avait des rapports de contiguite, que ce n'est qu'apres 

 quelque temps d'une attention soutenue, que nous sommes 

 parvenu alareconnaitre, et al'isoler sans efforts." Ibid, p. 22. 

 Now the truth is, that M. Coste simply deroulait mem- 

 branes that had been deroule before, and which had return- 

 ed to the corrugated or pelotonne state in which they had 

 been hardened by the alcohol, during the period of a voy- 

 age from Australia to London. And I need not state to 

 the practical anatomist, that an animal membrane so coagu- 

 lated and hardened, always retains its corrugations, unless 

 they are artificially and forcibly obliterated. But as after 

 my dissection of the ovum in question, in which I remov- 

 ed the chorion for a more detailed and microscopical inves- 

 tigation, I replaced the foetus and its vesicular appendages 

 in the uterus from which I had taken them ; so when they 

 were a second time removed to be exhibited to M. Coste, 

 they presented the appearances described by M. Gerbe,. and 

 to which I shall presently refer. But I cannot allow M. 

 Coste's statement, that the allantois was confounded with 

 the umbilical vesicle, to have the chance of passing into 

 the records of embryological science, without entering a- 

 gainst it a formal negation. M. Coste's description of the 

 adhesion of the allantois to the umbilical vesicle, and of 

 the difficulties he encountered in detecting it, repose, like 

 his description of the chorion of the same ovum, on pure 

 induction. 



Both M. Gerbe and myself have given figures of the allan- 

 tois in question. It is not a microscopic object. — The value 

 of its discovery does not rest upon the acute eye and rare 

 skill which its detection demands in the anatomical observer, 

 but upon the physiological conclusion to be deduced from it, 

 and its application to the general analogies of embryological 



