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The true corpora lutea arise from follicles in which the ova have become mature and from which they have escaped through the surface of the ovary. Buds from the theca interna invade the follicle and form the connective tissue of the corpus luteum.
Boils are most frequently met with on the back of the neck and the buttocks, and on other parts where the skin is coarse and thick and is exposed to friction and pressure. The occurrence of a number or a succession of boils is due to spread of the infection, the cocci from the original boil obtaining access to adjacent hair follicles.
Somewhat similar processes take place in the ovaries of Teleostean fishes, as I know from my own observations, but no corpora lutea are formed in these, although the degenerating follicles in course of absorption correspond to corpora lutea. Journ. Mic. It then remains without much change till parturition, after which it shrinks and is absorbed.
The skin consists of two layers, the derma, or true skin, and the epidermis, or cuticle. It is the principal seat of the sense of touch, and on the surface of the upper layer are the sensitive papillae, which receive and respond to impressions; and within, or imbedded beneath it, are organs with special functions, viz., the sweat glands, hair follicles and sebaceous glands.
Dermoid cysts of the ovary may consist only of a wall of connective tissue lined with epidermis and containing distinctly epidermic scales which, however, may be rolled up in firm masses of a more or less soapy consistency; this variety is called by Orth epidermoid cyst; or, according to Warren, a form of cyst made up of skin containing small and ill-defined papillae, but rich in hair follicles and sebaceous glands.
The organ present was small, 3/4 inch long by 1/2 inch broad, and microscopic sections showed in one part actively growing areas of tubular gland structure in some of which bodies like spermatozoa could be detected, while in another were fibrous tissue with degenerating cysts. The latter appear to have been degenerating egg follicles.
Numbers of ova die without reaching maturity, the follicular cells degenerate, and the follicle becomes filled with the cells of the theca interna, which have a resemblance to those of the true corpus luteum. These degenerate follicles have been termed spurious corpora lutea, or atretic vesicles. The interstitial cells are the remains of these atretic vesicles.
So perfect is the imitation of a leaf in structure and articulation, that this amazing insect when at rest is almost undistinguishable from the foliage around: not only are the wings modelled to resemble ribbed and fibrous follicles, but every joint of the legs is expanded into a broad plait like a half-opened leaflet.
The bulk of the entire organ consists of connective tissue, in which lie imbedded the Graafian follicles or ovisacs, in which the ova are contained. These follicles or ovisacs are minute cells which are packed immediately beneath the surface, where they occur in all stages of development.
Then the Graafian follicles containing the ova break and these latter enter the uterus for fertilization. If fertilization takes place, the fertilized egg buries itself in the wall and development of the embryo proceeds. Menstruation stops, the calcium salts being required for the growing embryo.
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