Volume 2

Researches in embryology. Ser. 1-2. / [M. Barry].

  • Barry, M. (Martin), 1802-1855
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: Researches in embryology. Ser. 1-2. / [M. Barry]. Source: Wellcome Collection.

    28/100 (page 324)
    present in fig. 108, and the condition to be next described. The figures given, how- ever, will suffice to show the nature of the process, which may, perhaps, be analogous to that observed by PoucHET-f' in the ovum of a species of Limnaeus. Possibly also, the divisions and subdivisions first noticed by Prevost and Dumas in the ovum of the Frog, and now known to occur in the ova of other Batrachian Reptiles, as well as in those of certain Fishes, may be referable to aprocess of the same kind:}; (par. 307. 318.). Ninth Stage of Development. 178. An ovum of sixty-three hours, and of f, is represented in Plate VI. fig, 109. It was found in the Fallopian tube within about an inch of the uterus. The vesicles seen in the centre of the ovum—still minuter than those in fig. 108, and much more numerous—had ceased to be transparent, and were punctate from dark globules, apparently on their outer surface. The vesicles were nearly of equal size, and measured each about The structure formed by those vesicles presented a curious resemblance to a mulberry. In the ovum, fig. 109, this mulberry-like object had a diameter of The membrane f was irregular in its thickness, and at one part had become very thin (par. 190.). Plate VIII, fig. 128. represents the same ovum crushed. The chorion {eho.) became elliptical (pars. 172. 222.), a change in form not participated by the membrane The contents of the ruptured membrane f, pro- ceeding no farther than the dotted line, showed this to be the inner surface of a thick membrane—the chorion—which (inner surface) had been concealed by an equal re- fracting power in the fluid /k The fluid f'^ in this instance had a tinge of yellow. 179. Von Baer found a little body in the uterus of the Dog, near the tube, which seems to have been an ovum in a state resembling that of the above. He describes it as consisting of a minute central sphere which was opake, with a transparent halo or periphery. The central sphere (my mulberry-like structure?) he conjectures may have been the vitellus or future intestinal sac, and the periphery he supposes was the “ membrane corticale.” Tenth Stage of Development. 180. Seven ova, one of which is exhibited in Plate VI. fig. 110, were found in the Fallopian tube within about three quarters of an inch of the uterus. The mulberry- like structure measured presented a greater number of vesicles—which were still somewhat smaller than the last—and the interior of its vesicles was more distinct. Their increased transparency seemed partly referable to the absence of dark globules seen in the preceding stage. Having a high refracting power, their outline was ex- tremely well defined and sharp; more so than I have been able to represent it with a pencil. Within each vesicle was seen an object § resembling the “germinal vesicle- t Froriep’s Notizen, No. 138, Julii 1838. X Schwann has suggested that the divisions in question in the ovum of the Frog, may, perhaps, be reducible to a “cell’’-formation (/. c. pp. 61, 62.). § In one instance two of such objects were observed in the same vesicle (par. 317. Note.).