DUKATION OF PREGNANCY 43 



This tumor could be felt ou internal and external exploration. 

 Bruckiniiller mentions in his pathological zootomy that Wolff 

 found a fibrous polypus in the uterus of a cow weighing 

 200 lbs. Kehm found in the uterus of a cow supposed to be 

 pregnant an atheromatous cyst (steatoma) of 50 lbs. 



At times one finds leiomyoma of great circumference. 

 Also, a diffuse, sarcomatous infiltration of the uterine walls may 

 result in an enormous increase of size ; also tuberculosis of the 

 uterus, if it attacks the serous membrane by continuity (Oster- 

 tag). All layers of the wall are then infiltrated and enormously 

 thickened. Echinococcosis of the liver may enlarge the liver 

 to such an extent that it expands the abdomen sufficiently to 

 simulate pregnancy (Harms). Palpation of the right ab- 

 dominal region behind the last rib, as well as rectal exam- 

 ination, with consideration of the other phenomena, are 

 sufficient to avoid an error. 



Obesity. — Very fat cows with great abdominal circumfer- 

 ence, the result of an undue accumulation of adipose tissue, 

 may be thought to be pregnant, especially as the udder also 

 becomes enlarged. A simple examination will allow us to 

 make a correct diagnosis. 



All these abnormalities resemble pregnancy. A close 

 examination can prove the absence of pregnancy, while doubts 

 often prevail as to the exact nature of the abnormality. 



7.— Duration of Pregnancy. 



The time elapsing between conception and expulsion of 

 the foetus, and during which the calf is fully developed in the 

 cow, is about nine months, or thirty-nine to forty weeks. The 

 shortest period of gestation, according to Dietrichs, is 210 

 • days, the longest 335, the average 286 days (Franck). 



Baumeister and Rueff put the average period of pregnancy 

 at 285 days, the shortest 240, the longest 330 days. 



The cows of the "Rijks Veeart-senijschoor' at Utrecht 

 average 40 weeks, heifers one or two days less. Many factors 

 may influence this period. "We know that primipara? carry 



