The early development of the marsupialia, with special reference to the native cat (dasyurus viverrinus) / by J.P. Hill.

  • Hill, J. P.
Date:
[1910?]
Catalogue details

Licence: In copyright

Credit: The early development of the marsupialia, with special reference to the native cat (dasyurus viverrinus) / by J.P. Hill. Source: Wellcome Collection.

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    abnormal), there can be little doubt that Dasyurus, like various other Marsupials (e.g. Perameles, Macropus, etc.), has suffered a progressive reduction in the number of young reared, but even making due allowance for that, the excess in production of ova over requii’eraents would still be remark- able enough. Whether this over-production is to be correlated in any way with the occurrence of abnormalities during early development or not, the fact remains that cleavage abnor- malities are quite frequently met with in Dasyurus. Technique.—As fixatives, I have employed for ovaries the fluids of Hermann, Flemming, Ohlmacher, and Zenker; for ova and early blastocysts, Hermann, Flemming, Perenyi, and especially picro-nitro-osmic acid (picro-nitric acid [Mayer] 96 C.C., 1 per cent, osmic acid 2 c.c., glac. acetic acid 2 c.c.); for later blastocysts, the last-named fluid especiall}'^ also picro-corrosive-acetic aud corrosive-acetic. To facilitate the handling of ova and early blastocysts during embedding, I found it convenient to attach each specimen separately to a small square of pig’s foetal membrane by means of a dilute solution of photoxylin (1 to 2 per cent.), Orientation of the specimen was then easily effected during final embedding, under the low power of the microscope. The larger blastocysts were double-embedded in photoxylin and paraffin, the cavity of the blastocyst being tensely filled with the photoxylin solution by means of a hypodermic syringe fitted with a fine needle. For the staining of sections, Heidenhain’s iron-htema- toxylin method proved the most satisfactory, and was almost exclusively employed. Entire portions of the blastocyst wall were stained either with Ehrlich’s or Delafield’s haematoxylin. I am much indebted to Mr. L. Scbaeffer, of the Anatomical Department of the University of Sydney, and to Mr. F. Pittock, of the Zoological Department, University College, for invaluable assistance in the preparation of the photo- micrographs reproduced on Plates 1—5, and also to Mr. A. Cronin, of Sydney, and Miss M. Rhodes, for the drawings fi’om their respective pencils reproduced on Plates 6 aud 7.