A text-book of animal physiology : with introductory chapters on general biology and a full treatment of reproduction, for students of human and comparative (veterinary) medicine and of general biology / by Wesley Mills ... with over 500 illustrations.
- T. Wesley Mills
- Date:
- 1889
Licence: Public Domain Mark
Credit: A text-book of animal physiology : with introductory chapters on general biology and a full treatment of reproduction, for students of human and comparative (veterinary) medicine and of general biology / by Wesley Mills ... with over 500 illustrations. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
147/750 page 115
![parts of the mucous lining of the uterus undergo softening and fatty degeneration, they are thrown off and renewed at these periods {catamenia, menses, etc.), provided pregnancy does not take place. In mammals below man, in their nat- ural state, pregnancy does almost invariably take place at such times, hence this exalted activity of the mucous coat of the uterus, in preparation for the reception and nutrition of the ovum, is not often in vain. In the human subject the menses appear monthly; pregnancy may or may not occur, and consequently-there may be waste of nature's forces; though there is a certain amount of evidence that menstruation does not wholly represent a loss; but that it is largely of that char- acter among a certain class of women is only too evident. As can be readily understood, the catamenial flow may take place prior to, during, or after the rupture of the egg-capsule. As the uterus is well supplied with glands, during this period of increased functional activity of its lining membrane, mucus in considerable excess over the usual quantity is dis- charged ; and this phase of activity is continued should preg- nancy occur. All the parts of the generative organs are supplied with muscular tissue, and with nerves as well as blood-vessels, so that it is possible to understand how, by the influence of nerve- centers, the various events of ovulation, menstruation, and those that follow when pregnancy takes place, form a related series, very regular in their succession, though little prominent in the consciousness of the individual animal when normal. The Nutrition of the Ovum (oosperm). This will be best understood if it be remembered that the ovum is a cell, undifferentiated in most directions, and thus a sort of amoeboid organism. In the fowl it is known that the cells of the primitive germ devour, amoeba-like, the yelk-cells, while in the mammalian oviduct the ovum is surrounded by abundance of proteid, which is doubtless utilized in a somewhat similar fashion, as also in the uterus itself, until the embryonic membranes have formed. To speak of the ovum being nour- ished by diffusion, and es])ecially by osmosis, is an unnecessary assumption, and, as we believe, at variance Avith fundamental principles; for we doubt much whether any vital process is one of pure osmosis. As soon as the yelk-sac and allantois have been formed, nutriment is derived in great part through](https://iiif.wellcomecollection.org/image/b21212867_0147.jp2/full/800%2C/0/default.jpg)
