Etiology, Pathogenicity. 741 



cultures one end is frequently club-shaped, and sometimes 

 branches (Fig. 125). 



Staining. The bacillus stains easily but not uniformly with aqueous 

 as well as with carbolized aniline dyes, giving the appearance of seg- 

 ments separated by clear spaces ; the Gram and Gram-Weigert methods 

 give negative results. 



Cultivation. The bacillus of abortion 

 grows especially well in a pure oxygen at- 

 mosphere, or in air with low oxygen con- 

 tents, while in the total absence of oxygen 

 it grows only with difficulty, and in ordi- 

 nary atmosphere only after it has gradually 

 become accustomed to such environment. 

 Cultures made according to these conditions 

 give particularly good results in or upon 

 gelatin-agar, a combination of agar, gelatin 

 and blood serum, as well as in glucose-agar. 

 Upon the surface of such media, kept at 

 body temperature there appears very fine, Fig. 125. Cory neb acterium 



flat, conical, evenly rounded, on transmitted abortus infeotiosi. Two-day- 

 light, bluish transparent colonies which even o^'^ ^^a.^ cultures ; eartol f uchsin. 

 if thinly seeded reach at most the size of a 



pin head. "When the material to be examined is mixed with the media 

 there develop, at a fixed distance from the surface and downward, 

 numerous similar colonies closely placed (Fig. 126). Coagulated calf 

 serum becomes liquefied in the vicinity of the colonies. In peptone 

 bouillon and in liquid blood serum, few small white granules form. 

 Milk becomes coagulated. Potato cultures show a marked resemblance 

 to a culture of the bacterium mallei (McFadyean & Stockman). 



Tenacity. In cultures the bacillus dies within two weeks (Nowak found, 

 however, that agar cultures were even after two years still capable of development. 

 A temperature of 55° C. will destroy the organism in 3 minutes. It is destroyed 

 by 0.05% corrosive sublimate solution in 15 seconds, by 1% carbolic acid in 

 1 minute, by 2% acetic acid in two minutes, by 1% acetic acid in 20 minutes 

 (Preisz). On the other hand it may retain its virulence for many months in 

 uterine secretions if preserved sterile, also if uncontaminated inside of the womb 

 and in the dead foetus (Bang). 



Pathogenicity, In Bang's investigations the injection of 

 pure cultures into the vagina of pregnant cows and ewes pro- 

 duced in 8 to 10 weeks either abortion or premature birth; 

 in these cases large numbers of bacilli were present in the 

 vaginal discharge, in the exudate on the surface of the coty- 

 ledons and the chorion. Injections of 8 and 18 cc. of culture 

 respectively into the circulation of pregnant ewes produced 

 fever lasting several days, whereupon these animals gave birth 

 after 7 and 12 days to small lambs. Bang's experiments, the 

 results of which were subsequently confirmed by McFadyean 

 & Stockman, demonstrated that the feeding of cultures or 

 exudate to cows, ewes and goats results in abortion after 1 

 to 2 months, with the characteristic changes in the fetal mem- 

 branes and cotyledons. Finally it was also possible to produce 



