140 OBSTLTSICAL PIirSIOLOGr. 



troublesome, or unsteady when in "heat/' are nearly always gentle and 

 tractable when in foal : the genital excitement which caused their 

 capriciousness or viciousness being allayed, they are no longer under its 

 induence. This change, when occurring after copulation, is a valuable 

 sign of successful impregnation ; and though it may sometimes fail, yet 

 whtn present it can scarcely lead to a mistake. If, on the contrary, 

 the animal has not been fecundated after one or more coverings, 

 if previously vicious its vices become exaggerated when again put to the 

 Horse. 



In the Cow a similar phenomenon may be remarked, though it is not 

 so frequent or marked as in the Mare. 



The other animals are seldom so irritable in their disposition as to 

 lead anyone to notice a similar change in them. 



A tendency to fatten is such a notorious consequence of impregna- 

 tion, that with the Cow and Sheep graziers usually resort to it in order 

 to get these animals in good condition for market, when they are in- 

 tended for slaughter. But this aptitude is most marked in the early 

 months of gestation ; for in the Cow towards the last three months, and 

 in the Sheep and Pig at the last month, when the mammte begin to 

 enlarge, there is a tendency to lose condition. According to the 

 butchers, there is less internal fat, and the animals altogether are not 

 so heavy as they appear externally, when gestation has advanced. It 

 often happens, particularly with Cows, that the appetite is depraved, 

 the animals eating earth, drinking filthy water, Ucking walls, and 

 gnawing innutritions substances. 



Coincidentally with the progress of gestation, those animals employed 

 in labour for speed or draught lose their vigour somewhat, particularly 

 towards the end of pregnancy: they become "soft," and their paces 

 slower and heavier — consequently, they require more urging to make 

 them perform a certain amount of work. They, if Mares, trot, gallop, 

 and jump with more fatigue, and yield themselves far less readily to 

 inordinate exercise than before — either because their temperament 

 alters, their instinct urges them to preserve their progeny, or the fcetus 

 itself physically embarrasses them in their movements. 



But this is not always a sure sign : for sometimes, though rarely. 

 Mares will perform their work with the same energy and speed as 

 before conception, even up to a very brief period before parturition 

 commences. Taken with other signs, nevertheless, this may afford 

 assistance in diagnosing gestation. 



At pasture. Cattle and Sheep are more tranquil, and rest much; as do 

 also Pigs and Bitches during this period. 



2Iatenal Signs. 



The material, physical, or objective signs are those depending upon 

 the change in volume of the abdomen and the mammc?, the appearance 

 of the milk in the latter, alterations in the composition of the urine, and 

 increase in iceight of the animal. 



The abdomen enlarges in every direction, and at the same time 

 changes its shape. It descends or " drops," becoming larger inferiorly; 

 the fianks become hoUow, and the spine appears more concave in the 

 dorso-sacral region ; while the lateral portions of the croup sink so 

 much as to make the sacrum and haunches towards the root of the tail 

 look more salient. These phenomena are progressively developed as 

 gestation approaches its term, when they are very evident. In the 



