Researches in embryology. Third Series: a contribution to the physiology of cells

Abstract

In the paper referred to, the author had shown, that after the ovum of the Rabbit has entered the Fallopian tube, cells are found collected around its thick transparent membrane or “ zona pellucida” ; which cells, by coalescing, form a thinner membrane—the incipient chorion. He now adds, that the formation of this thinner membrane does not exhaust the whole layer of these cells; but that a stratum, of them is found remaining on, and entirely surrounding the “ zona”, after the thinner membrane has risen from it. The fluid space also, between the “ zona” and the thinner membrane, presents a large number of cells or discoid objects, each of which contains a brilliantly pellucid and highly refracting globule. In some parts, several of these discs, closely joined together, have the appearance of shreds of membrane ; in others, there are found pellucid globules, some of which are exceedingly minute. The discs now mentioned collect at the periphery, for the thickening of the chorion. They seem to proceed from the region of the “ zona ” ; and probably have their origin in the cells by which the latter is surrounded. If so, the author thinks we cannot suppose them to arise in any other way than that which, according to his observations, appears to be the universal mode of reproduction ; namely, by division of the nuclei of the parent cells. Nor can we suppose that minuteness is any hinderance to their subsequent increase by the same means.