138 OBSTETIUCAL FHYHIOLOGY. 



vary occasionally, and even frequently, owing to the active reflex move- 

 ments which it performs ; and to these energetic movements, it cannot 

 be doubted, are due the difficult presentations which the fojtus offers so 

 frequently (at least in some species) at birth. 



SECTION III.— SIGNS OF PREGNANCY. 



Having traced thus far the process of utero-gestation, we have now 

 to study the signs by which this process reveals itself. This study is 

 very important, in several respects, to the comparative pathologist, or 

 rather to the veterinary surgeon, whose science extends beyond patho- 

 logy, and who is frequently called upon to give an opinion as to whether 

 an animal is or is not pregnant. 



The signs which announce pregnancy are numerous and varied, though 

 they are not all reliable, and several are very deceptive and not peculiar 

 to gestation. Indeed, it has frequently happened that animals whose 

 condition was not at all certain have brought forth young, and others 

 have done the same without giving rise to any suspicion that they were 

 pregnant ; though it must be remembered that at first there is nothing 

 present to guide one in forming an opinion as to the animal having 

 conceived. 



Nevertheless, in order that a correct opinion may be arrived at, the 

 most equivocal signs must be taken into consideration, as well as those 

 which are, so to speak, unequivocal — indeed, they ought to receive, for 

 this very reason, more than ordinary attention ; as it is a matter of 

 much moment, and particularly in cases of jurisprudence, that the 

 veterinarian should be able to speak positively as to the existence or 

 absence of pregnancy. 



The diagnosis of pregnancy is not always easy, and it is all the more 

 difficult as the stage is early. 



In order to study the signs of pregnancy conveniently, it is usual to 

 divide them into two categories — the certain and the prohahle signs ; or 

 into three categories as follows: 1. The rational, physiological, or sub- 

 jective signs ; 2. The material ox objective signs; 3. The sensible signs 

 which are derived from observation and manipulation, in order to ascer- 

 tain the presence of the foetus. In this study, of course the larger 

 animals will be more particularly referred to, because of their relatively 

 higher value and importance, and their longer period of gestation ; and 

 also because the veterinary surgeon is most frequently consulted as to 

 their condition. 



national Signs. 



There are several rational signs due to the modifications broiight about 

 in the economy of the pregnant animal, and manifested by alterations 

 in temperament, character, and aptitudes. 



The cessation of heat or rutting is, perhaps, the earliest subjective, 

 though it is certainly not the most cei'tain, sign of gestation, and may 

 even lead to mistakes. It is usually manifested soon after conception 

 has taken place (six or eight days), by a decrease in the venereal excite- 

 ment which marks the period of oestrum ; the animal, as has been men- 

 tioned, is comparatively tranquil and does not exhibit any desire for the 

 male, neither does she neigh, paw, or show the usual concomitant 

 symptoms of "heat." If the male approaches, the sexual desires are 

 not excited, and in refusing him the female may even resort to aggres- 



