138 OBSTETRICAL PHYSIOLOGY. 



Rainard, Trasbot, and others, have not succeeded in detecting these 

 sounds ; and I have on several occasions practised auscultation on preg- 

 nant Mares, but have failed to distinguish the foetal pulsations. 



But there is no reason why, as suggested by M. Trasbot, the uterus 

 should not be auscultated from the cervix, by a long special stethoscope 

 — or rather " metroscope " — introduced by the vagina, and its wide end 

 resting on the cervix. The intestinal noise would be evaded in this way, 

 and the fluids surrounding the foetus being good conductors of sound, the 

 beats of his heart should be distinctly heard, if it is alive. Nauche, so 

 long ago as 1826, and Verardini, in 187 1, have spoken strongly in favor 

 of this iiitra-vdgina auscultation in the human species. 



From what has been said of the signs of pregnancy, it will be perceived 

 that, in the early period of this condition, there is but little more than 

 supposition to guide us, the presumptions becoming stronger as the 

 physical and other indications are more marked. It is only, however, 

 towards the middle period, when all the rational and physical signs are 

 present, and when the condition of the uterus has been ascertained by 

 the exploratory manoeuvres above described, that we can affirm, without 

 the danger of error, the existence of pregnancy. And when a doubt 

 chances to prevail at this stage, it is well to remember that this condition 

 may exist without being accompanied by very evident signs, and that a 

 hasty conclusion must not be drawn. When, for instance, some rational 

 signs present give rise to the presumption that an animal is pregnant, but 

 no physical indication reveals this state, the examinations must be re- 

 peated before a final decision is arrived at. The value of experience" 

 and observation, when added to theoretical knowledge, is well displayed 

 in this branch of veterinary science. Not unfrequently the diagnosis of 

 pregnancy is surrounded by great difficulties, and a guarded opinion 

 must be given. 



SECTION IV. DURATION OF PREGNANCY. 



The duration of pregnancy varies* considerably in different species of 

 the domesticated animals \ and even in the same species, there are indi- 

 vidual variations which, though not very great, are yet important. From 

 the doe Rabbit, which carries its young only twenty-eight to thirty days, 

 to the female Elephant, whose period of pregnancy is, according to 

 report, two years, there are a number of intermediate terms ; and it is 

 scarcely possible to establish a satisfactory relationship between the 

 duration of gestation and the other conditions of organization — such as 

 size or longevity. In closely allied species, and which may couple and 

 produce hybrids — as the Horse and Ass, Sheep and Goat — the period is 

 pretty nearly the same. 



With regard to breeds, Wilhelms has remarked that the Hungarian 

 Cow av,erages ten days more than the Dutch Cow. With a male foetus, 

 the duration of gestation is greater than in the case of a female. It has 

 even been remarked that the male parent may have an influence in this 

 direction. For instance, a Mare which has been put to a thorough-bred 

 Horse will be longer pregnant than when impregnated by a common- 

 bred stallion ; and the Mare which has been fecundated by a stallion 

 Ass goes longer than when put to a Horse. The duration of pregnancy 

 also depends upon the age of the female, and her strength and condition ; 

 a weakly or worn animal does not go so long as one which is strong and 

 well fed. 



