150 White Sconrs of Suckliii,s;s. 



affected with diarrhea (Dleckcihoff). Besides affected animals 

 may spread the contagion among sucklings of other species of 

 animals, especially lambs may become affected when an infected 

 calf is placed among them (Kotelmann). 



The possibility of an intrauterine infection was proven by 

 Kitt when he injected 3 cc. of a washed agar culture of colon 

 bacilli intravenously into a cow in advanced pregnancy. This 

 immediately caused a profuse diarrhea in the calf which was 

 born eight days later. 



Newborn animals are more susceptible or predisposed to 

 the disease immediately after birth, while later the suscepti- 

 bility diminishes rapidly. As a matter of fact the animals 

 become affected in the majority of cases within 24 to 48 hours, 

 much more rarely from 3 to 8 days after birth, whereas older 

 animals usually do not contract the disease. Conditions which 

 predispose the body, such as poor nutrition, congenital weak- 

 ness, etc., favor the development of the disease, particularly as 

 the animals have not a great resistance in the first days of 

 life. Besides, the withholding of colostral milk from the calf 

 and the immediate feeding of boiled milk after birth results 

 almost always in the appearance of the disease. 



An abnormal composition of the mother milk, high fat contents 

 or the opposite too high dilution, as well as indirectly the feeding 

 of the mothers with oil meal cake or swdll (Kovacsy) may have an 

 influence on the development of the disease, since such conditions 

 favor an abnormal multiplication of colon bacilli in the intestines of 

 sucklings. 



Pathogenesis. Bacteria which accumulate in great num- 

 bers in the intestinal tract of sucklings enter the tissues of the 

 intestinal mucous membrane, the lymph spaces and the hnnph 

 follicles. The penetration of these organisms in the first days 

 of life is facilitated by the absence of the ''mucous layer" 

 (Disse) from the intestinal epithelium which at a later age 

 prevents to some extent the penetration of the bacteria. From 

 the intestinal walls the bacteria enter the mesenteric lyiu-ph 

 glands and cause acute swelling. Later they may enter the 

 blood circulation and flood the entire body. 



According to Jensen white scours is not a simple inflamma- 

 tory condition of the digestive tract, but an inflammatory 

 process complicated with a septicemic condition, which is caused 

 by the entrance of the bacteria into the blood circulation. It is 

 very probable that the manifestations of the disease are to 

 some extent caused by toxic products of the bacteria. Although 

 filtrates free of bacteria from virulent colon cultures have 

 proven harmless (Jensen), the negative results do not exclude 

 the development of toxins in the animal body. Bacilli of the 

 paratyphus group B produce severely acting toxins even in 

 artificial culture (see page 148). 



