322 Manual of Veterinary Microbiology. 



pleuro-pneumonia. A pig also took the disease bj 

 pulmonary injection; the sheep and the dog are re- 

 fractory (Poels). The microbe is described as a facul- 

 tative parasite capable of living in the soil, which 

 fact, according to Poels, explains the persistence of 

 the disease on an infected farm. M. Galtier thinks 

 that the latter ought to be attributed to the mothers 

 (see page 325). However that may be, its transmis- 

 sion from calf to calf must be admitted ; the virulent 

 germs are spread around with the expectorations and 

 perhaps with the excrements (Poels claims to have 

 found the germs in all the organs). These microbes, 

 and especially those of the nasal discharge, con- 

 taminate the vessels in which milk is fed to the dis- 

 eased, and the same vessels are then used for other 

 animals.* 



The microbe of this pleuro-pneumonia of calves 

 belongs to the great class of ovoid bacteria showing 



* [In the diarrhoea or dysentery of young calves known as 

 "white scours" [Ger. Kalberruhr) Jensen (1892) discovered in 

 the blood, spleen, liver, kidneys and lungs, as well as in the mu- 

 cous membrane of the intestine, oval bacteria, isolated or asso- 

 ciated in pairs or short chains, staining at the extremities only, 

 and easily cultivated in the various artificial media. Bouillon 

 cultures fed to young calves in doses of 5 cc. produced the charac- 

 teristic diarrhoea and death in from one to two days. From the 

 contents of the intestine of healthy calves he isolated apparently 

 the same germ but found it destitute of pathogenic properties. 

 Jensen came to the conclusion that the microbe is a facultative 

 parasite, a usually harmless inhabitant of the intestinal canal but 

 one which under certain abnormal conditions of the intestine 

 (perhaps attributable to the diet) acquires pathogenic properties 

 which become increased by subsequent passage from calf to 

 calf.— D.] 



