142 OBSTETRICAL PHYSIOLOGY. 



observed in primiparge take place, but the mammae may be later in 

 enlarging. 



Though, in a natural state, the mammary glands are only intended 

 to furnish aliment to the young creature until it is sufficiently strong 

 and active to find its own food, when they suspend their function ; yet 

 domestication has greatly modified their secretory power in some 

 species — as with the Cow, Goat, and sometimes the Ass and Sheep — 

 and the secretion of milk becomes an almost permanent function. Not 

 only this, but at times the secretion, as observed in the unimpregnated 

 Bitch, is very anomalous and unnatural. In the non-pregnant female 

 of various species — not excepting the human species — the secretion may 

 appear naturally, or be induced by mulsion or frequently repeated 

 suction of the teats, even in very young creatures, a short time after birth ; 

 and what is more astonishing, male animals have in rare instances 

 assumed a function which is always looked upon as specially charac- 

 teristic of the female sex at the maternal period. So early as the days 

 of Aristotle — who mentions a he-goat which yielded milk — this strange 

 phenomenon has been at times observed ; and M. Lecoq testifies to 

 an Ox, in process of fattening, having the four rudimentary mammae 

 increased in volume and yielding milk which furnished cream, and 

 became casein when an acid was added to it. 



Certain alterations in the composition of the urine have been re- 

 ported by M. Keiner of Giinsback, which, with other circumstances, 

 might, if found to be trustworthy, be valuable as an aid in the diagnosis 

 of pregnancy. He has discovered that the salts of lime in the urine 

 diminish in proportion as the foetus requires these for the formation of 

 its bones ; and his discovery has been tested by a chemist whose 

 analysis of this fluid, obtained from a pregnant Mare, shows that the 

 lime lessens very much as the time for parturition draws nig'.i. At the 

 fifth or sixth month it is diminished 55 per cent., and to 70 per cent, 

 from the sixth to the ninth month. 



It has been proposed to weigh animals which are suspected to be 

 pregnant, at certain intervals ; an increase in weight being an evident 

 accompaniment of growth in the foetus. In this direction, Eueff has 

 recorded that Mares, towards the fourth or fifth month of pregnancy, 

 have shown an average increase in weight of more than eleven pounds 

 in eight days, and he particularly recommends this aid to diagnosis, 

 which appears to be most useful at mid-term. 



It may be noted as an additional aid in diagnosis, that with the 

 progress of gestation the mucous membrane lining the vulva and 

 vagina becomes swollen, and assumes a red or bluish-i-ed hue, instead 

 of its usual pink colour ; and towards the termination of pregnancy, 

 the secretion of vaginal mucus, particularly in the Cow, is largely 

 increased. 



All these numerous signs are by no means to be implicitly relied upon, 

 however, as they are not infallible in proving the existence of pregnancy 

 in every case ; some of them are only noticeable at a late period, while 

 others may be absent. It is necessary in taking them into considera- 

 tion, to distinguish those animals which are kept at pasture and destined 

 for breeding, from those which are kept in the stable and used for 

 various purposes. With the first, the cessation of oestrum and the 

 refusal of the male are almost certain indications of conception ; while, 

 with the latter, the same phenomena may be the result of fatigue or 

 bad food and mismanagement. 



