Signs of Pregnancy ' 389 



are alterations in the composition of the urine of the pregnant 

 animal, consisting chiefly in a decrease in the salts of lime, but 

 the data upon this point are not sufficient to warrant any definite 

 conclusion. 



Some have proposed to weigh animals suspected of being 

 pregnant, but the weight of animals varies so greatly, as a result 

 of the character of food, work or health, that no deductions can 

 safely be drawn in this way. 



Finally, when parturition is near, there is an increased vascu- 

 larity of the mucous membrane of the vulvar opening. 



In the cow, a further sign of pregnancy, applying only near the 

 close of gestation, is that of sinking of the hips owing to relax- 

 ation of the broad sacro-sciatic ligaments of the pelvis. As al- 

 ready noted similar signs are regularly observed in sterility es- 

 pecially when due to diseased ovaries. 



None of the foregoing signs of pregnancy are wholly reliable. 

 While they generally answer the purposes of the breeder, there 

 are frequent exceptions which may lead to more or less serious 

 error. Any one of the foregoing symptoms of pregnancy may 

 be induced by other causes and any one of them may be absent 

 nearly or quite to the time of parturition. 



Positive or Direct Signs. 



We can only determine the existence of pregnancy positively 

 by observing the presence of the fetus in the uterus by some un- 

 equivocal means. To this end we have definite means : i , by 

 vaginal, rectal or abdominal manipulations or by ballottement ; 

 2, by auscultation of the fetal heart-beat ; 3, by observing the 

 movements of the living fetus. 



The determination of the presence of the fetus in the uterus 

 by manual exploration is more or less available in all our domestic 

 animals when gestation is well advanced. In our larger her- 

 bivora it is not easy to feel the fetus through the abdominal 

 walls, because of their tension and firmness, but in the small 

 animals, like the bitch and cat, the fetuses may be somewhat 

 easily felt through the thin abdominal walls. 



In the larger animals, if the fetus is well back and a portion 

 of it projects into the pelvis, it may readily be touched and re- 

 cognized through the vagina. This method, however, is not so 



