Prevention and Treatment. 749 



Tafin and others, observed a gradual reduction, and finally a 

 complete disappearance of the disease from such treatment. 

 Haubold, Schlag, Vollrath and others, however, found this 

 treatment ineffective, and even in the favorable cases the dis- 

 appearance of the disease was probably the result of a disin- 

 fection which was carried out simultaneously. The same 

 probably would apply also to the internal administration of 

 carbolized water (l-iy2 liters of a 1% carbolic acid solution 

 once daily [Nuesch]), as well as the weekly prophylactic irri- 

 gations of the vagina of pregnant cows with 1/4 liter of a 

 21/4-3% solution, with which Horlyck and Dolmer have recently 

 obtained very good results. 



In order to prevent the introduction of the disease from 

 outside, newly purchased pregnant animals should be observed 

 carefully, and should be kept isolated until calving; further 

 animals with s^^nptoms of a uterine or vaginal catarrh 

 (leucorrhea!) should not be bred at least until completely re- 

 covered. The association with persons w^ho are employed in 

 infected premises should also be limited as far as possible. 

 In male animals which have served on other premises, it is 

 advisable to disinfect the prepuce and the penis before the 

 act of covering. Furthermore, each case of abortion should 

 be treated as if it were an infectious form of the disease, and 

 particularly does this appear to be necessary in those cases 

 where the abortion occurs under the above-described manifesta- 

 tions even in a herd which has been known to be free of the 

 affection. 



Females which have aborted one or more times should be 

 disposed of only if they fail to conceive after a subsequent 

 covering, provided that they have received suitable treatment. 

 By keeping pregnant animals the disease will be brought to a 

 standstill more quickly than if new susceptible material is con- 

 tinually added in their place (Bang). 



If the described method is carried out accurately it almost in- 

 variably succeeds in suppressing the disease. In already infected 

 animals abortion cannot be prevented, but the infection of healthy 

 animals can be prevented. Authoritative measures which would pre- 

 vent animals from infected herds being taken to markets, animal ex- 

 hibitions and public pastures, would considerably aid in the prevention 

 of the dissemination of the virus (such measures exist at present in 

 Norway). 



Immunization. Bang's most recent investigations indicate the 

 possibility of immunization of cattle, sheep and goats against the in- 

 fection. He found that several animals which repeatedly received in- 

 travenously living cultures (10 cc. each time) at least two months 

 before conception, carried the fetus to normal time in spite of the fact 

 that during their pregnancy they were infected per os with cultures 

 or exudates. As however the intravenous injection sometimes disturbed 

 the general health greatly, experiments were later undertaken on sheep 

 and goats with subcutaneous injections of cultures (5 to 7 times, a 



