366 Miscellaneous. 



were originated by M. Milne-Edwards. These doctrines may be 

 summed up in the thesis that this vascular system is lacunary, and 

 in communication both with the cavity of the body and with the 

 exterior world. M. de Quatrefages also taught, as early as 1844, the 

 existence of an extravascular circulation, among the Gasteropods 

 of the family Eolididae, which he classed among his " Gasteropodes 

 2}hlebenteres." Souleyet energetically opposed this notion, and 

 asserted the existence in these animals of a venous system, similar 

 to that of the higher animals. M. Eobin (1851), after carefully 

 criticising the works of Cuvier and of MM. Milne-Edwards, Quatre- 

 fages, Blanchard, and Owen, pronounced in favour of Souleyet and 

 the closed vascular system, and consequently against phleben- 

 terism. 



J^otwithstanding the objections of Souleyet and M. Eobin, not- 

 withstanding the anatomical researches of MM. Kcber and Langer, 

 notwithstanding the fine- injections of the latter, which have demon- 

 strated the existence of a system of capillary vessels and at the same 

 time the absence of an aquiferous system in these Lamelhbranchs, 

 notwithstanding all this, M. Milne-Edwards maintains to this day 

 the existence of a lacunar circulating system in all the MoUusca, 

 with vessels widely gaping in the cavity of the body and exter- 

 nally. M. "Wedl has just carefully resumed this study, and, like 

 Souleyet and M. Robin, M. Keber and M. Langer, he declares most 

 positively against M. Milne-Edwards. 



The method employed by M. Milne-Edwards was insufficient. He 

 contented himself with injecting a solution of chromate of lead into 

 the perivisceral cavity by a small opening made in the back or else- 

 where. M. Agassiz, by making injections through the mouth or the 

 anus, thought he could also demonstrate a direct communication 

 between the digestive organs and the circulatory system. M.Robin 

 has already characterized these processes as coarse. Thus, for in- 

 stance, it is certain that in opening the perivisceral cavity it is easy 

 to open at the same time a blood-sinus or some large vessel, and to 

 make the injection penetrate through this. 



M. Milne-Edwards cites in support of there being a communica- 

 tion of the vessels with the perivisceral cavity the following evi- 

 dence, which one cannot help thinking singular. When he examined 

 with the microscope the blood of the ventricle of the heart and the 

 perivisceral hquid in a hving Helix, he found the two liquids per- 

 fectly similar, both of them containing blood-corpuscles. Now it is 

 not possible to open the perivisceral cavity without cutting a quan- 

 tity of vessels, whose contents fall into the cavity. M. Wedl, on the 

 contrary, by making his injections through the heart, has ascertained 

 that in HeHx the injected mass does not penetrate into the peri- 

 visceral cavity, and does not go out at the exterior surface. 



It is remarkable that M.Milne-Edwards in his works never speaks 

 of the capillary vessels, which might lead one to suppose that he 

 has never seen them. Several naturalists whom this author ranks 

 among his adherents nevertheless differ from him on certain points. 

 Mr. Owen and M. Blanchard in particular never speak of true lacunae, 



