Obstetrics : A manual for students and practitioners / By Charles W. Hayt.

  • Hayt, Charles W.
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: Obstetrics : A manual for students and practitioners / By Charles W. Hayt. 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.

    23/226 (page 27)
    In the female: Abnormal formation of the genitais; Displacements of the uterus, obstructing the ascent of the semen; Vaginal or uterine secretions rendered so strongly acid or alkaline by disease that the spermatozoids are destroyed ; Tubal and ovarian diseases. Describe the changes which take place in the impregnated ovum during its passage to the uterus. As the ovule escapes from the ovary it takes with it some particles of the discus proligerus, which surround it as a thin layer of granular cells. B}'^ friction with the sides of the tube these disappear, and the zona pel- lucida is the outermost covering. It has now advanced some distance along the tube, and becomes invested with a covering of albuminous material. During this time the vitellus or yelk shrinks from its covering and the germinative vesicle disappears. The first indication of impreg- nation occurs when a small, clear vesicle appears in the centre of the yelk. This is called the vitelline nucleus, and is found in fifteen to thirty hours after fecundation. Now what is called segmentation of the yelk takes place. This consists in a breaking up of the vitellus. First. the vitelline nucleus divides into two nuclei, and then the yelk into two halves. The process continues: the two new cells are converted into four, the four into eight, and so on until a great number are generated. This forms a granular mass which from its resemblance to a mulberry is called the muriform body or morula. A clear fluid then accumu- lates in the centre, expanding the muriform body and pushing tlie cells together until their edges meet, forming an internal lining to the zona pellucida. This is the blastodermic membrane, and from it the foetus is developed. The ovum is now 2Vth of an inch in diameter, and has occupied about twelve days in its passage from the ovary to the uterus, which it has reached. What changes occur in the uterine mucous membrane to prepare it for the reception of the impregnated ovum ? At each menstrual period the mucous membrane of the uterus be- comes thickened and vascular, and when fecundation has occurred this change is much more marked, until the result is the formation of a dis- tinct membrane which has received the name of the decidua. This has three divisions: (1) The decidua vera. lining the entire uterine cavity, and undoubtedly the hypertrophied mucous membrane of the uterus. (2) The decidua reflexa, which surrounds the ovum, and is probably simply a growth of the decidua vera around the ovum at the point where it lies in the uterus. As the ovum grows this naturally stretches until it eventually (at the fourth month) comes in contact all around with the decidua vera. (3) The decidua serotina, which is that part of the decidua vera on which the ovum rests. At this point the placenta is developed. Thus it is seen that the three deciduae be-