130 OBSTETRICAL PHYSIOLOGY. 



proliferation of the corpuscles of the sub-epithelial connective tissue, so 

 that the glands are more widely separated ; while the uterine cotyledons 

 grow quickly, and there can be no doubt that new ones appear. 

 Rainard speaks of examining the uterus of several calves and lambs, 

 and finding only thirty or forty cotyledons ; while after parturition he 

 has counted more than a hundred ; and more recent observers have 

 testified to this fact. In the uterus of a six months pregnant Cow, 

 Franck found that the hoi-n containing the foetus had forty-seven coty- 

 ledons and weighed 3,54 pounds ; while the other horn had only forty- 

 two placentae, and weighed no more than 0,22 pound. 



In addition to these supplementary appendages of the mucous mem- 

 branes, a new glandular apparatus, of which no trace was to be found 

 previous to gestation, now makes its appearance in the form of a large 

 number of small openings in the mucosa, each leading into a depression 

 which was for a long time regarded as the dilated mouth of the tubular 

 or utricular glands, but which is really a " crypt " formed in the hyper- 

 trophied tissue of the uterus — a kind of open follicle placed in the inter- 

 glandular part of the mucous membrane. These crypts are new 

 structures, formed during pregnancy, and are for the lodgment of the 

 villi that project from the chorion of the foetus — being, in fact, the 

 maternal cotyledons or maternal portion of the placenta. They are 

 small straight depressions, lying more or less closely together through- 

 out the whole of the uterine mucous membrane of the Mare, their 

 cavity being lined by a layer of tessellated epithelium, and a very fine 

 capillary network surrounding each. In the Cow, these crypts are 

 assembled on the surface of the projections designated cotyledons, of 

 which they constitute nearly the entire mass during pregnancy. In 

 the Bitch they are only developed where the ovum is fixed, forming 

 then a glandular layer occupying the contour of the uterine cornu. 



The utricular glands do not open directly into crypts, nor is their 

 secretion poured into them, but on a definite surface of the mucous 

 membrane between the crypts, the size and areas of which correspond, 

 of course, to the size and arrangement of the foetal tufts. 



Between the foetal and maternal placentae there is always a layer of 

 epithelial cells of varying thickness, which represents the viemhrana 

 decidua or serotina of woman. If not during parturition, at least after- 

 wards, all placental mammals are more or less " deciduate." With the 

 Cow and Sheep, for example, large quantities of cells, possessing the 

 character of epithelial cells of the pits and crypts of the maternal 

 cotyledons, have been found, mingled with the villi of shed foetal cotyle- 

 dons, in the fluid extruded during and after parturition — showing that 

 a portion of the maternal structure is carried away at this time. The 

 crypts possess the sti-uctural characters of secreting organs ; and, indeed, 

 we cannot but look upon the maternal placenta and the remarkably 

 modified mucous lining of the uterus as a great secreting apparatus. 



In addition to the mucous membrane, the outer or serous membrane 

 is also hyper trophied, the broad ligaments are increased in every direc- 

 tion, but especially in length, and muscular fibres are abundantly 

 developed between their layers, in order to give them sufiicient strength 

 to sustain the weight of the uterus. In the Cow, the fibres even form 

 very distinct intercrossing fasciculi. 



The greatest increase of all noted in the texture of the uterus, occurs 

 in the middle or muscular tunic. There appears to be a vast multipli- 

 cation of the fusiform nucleated fibres going on during pregnancy, as 



