Volume 1

The works of Francis Maitland Balfour / edited by M. Foster and Adam Sedgwick.

  • Balfour, Francis M. (Francis Maitland), 1851-1882.
Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: The works of Francis Maitland Balfour / edited by M. Foster and Adam Sedgwick. Source: Wellcome Collection.

    233/948 (page 213)
    CHAPTER I. The Ripe Ovarian Ovum. The ripe ovum is nearly spherical, and, after the removal of its capsule, is found to be unprovided with any form of pro- tecting membrane. My investigations on the histology of the ripe ovarian ovum have been made with the ova of the Gray Skate (Raja batis) only, and owing to a deficiency of material are somewhat im- perfect. The bulk of the ovum is composed of yolk spherules, imbedded in a protoplasmic matrix. Dr Alexander Schultz^ who has studied with great care the constitution of the yolk, finds, near the centre of the ovum, a kernel of small yolk sphe- rules, which is succeeded by a zone of spherules which gradually increase in size as they approach the surface. But, near the surface, he finds a layer in which they again diminish in size and exhibit numerous transitional forms on the way to molecular yolk-granules. These Dr Schultz regards as in a retrogressive condition. Another interesting feature about the yolk is the presence in it of a protoplasmic network. Dr Schultz has completely confirmed, and on some points enlarged, my previous observa- tions on this subject'^ Dr Schultz's confirmation is the more important, since he appears to be unacquainted with my pre- vious investigations. In my paper {loc. cit.), after giving a description of the network I make the following statement as to its distribution. ^ Archiv fiir Micro. Anat.NoX. xi. 1875. 2 Quart, Journ. Micro, Science, Oct. 1874. [This edition, No. v.]