1090 EXPERIMENT STATION RECORD. 



and that thoy oontaiii unmoditied .spores. Their .special properties are 

 suppo.sed to l)e due to un alteration of the toxin under the influence 

 of heat. It wa.s found possible to prepare pure powdered vaccines. 

 Vaccination of cattle may be effected by the use of pure cultures 

 heated to a temperature of 70° C. for 2 hours. The partial immunity 

 thus produced may be completed by inoculation with a pure culture 

 which has not been subjected to heat. Animals thus treated resist 

 large doses of virulent fluid without reaction. This method has the 

 advantage of being convenient and practical. The horse and goat 

 treated with repeated intravenous injections of virulent fluid or pure 

 cultures produce an immunizing serum Avhich is possessed of prevent- 

 ive properties. It confers only a temporary immunity, and when 

 mixed Avith virus, neutralizes the effects of the latter without produc- 

 ing pernianont imnuuiity. 



Practical experience in vaccination against hog cholera, Graul 

 {Berlin. Thurdrztl. Wchnadir., WOO, No. 1^0, pp. 577-579).— Iw the 

 present article, the author conffnes his attention to the three problems 

 concerning the duration of immunity, indemnity for loss caused I)}" 

 inoculation, and inoculation l)v stock owners. According to the 

 author's ot)servations, the period of imnuuiity produced by ordinary 

 inoculation methods does not extend beyond (! or 7 months. It is 

 thought desirable, if possible, to bring about an inununity which will 

 endure for a full year. In some instances, losses occurred as a direct 

 result of preventive inocvilation. The author believes that the ques- 

 tion of indemnity for such losses must ultimately be regulated in a 

 legal manner. On the question as to whether untrained individuals 

 shall be allowed to inoculate animals, the author takes the position 

 that this is very undesirable. Trained veterinarians are sufficiently 

 numerous in all localities to be readily secured for this work in cases 

 of emergency, and far better and more satisfactory results are obtained 

 when such persons are engaged for the work than when inoculation is 

 left in the hands of more or less irre,sponsible individuals. 



Preventive and curative inoculations against hog cholera, P. 

 KiTT ^MoiHdsh. J Wild. Thlerh., m {1001), No. ^-o,pp. S7-Uni). The 

 author jjresents a critical historical account of the various methods 

 which ha\'e Ixhmi adopted in producing inununity against this dis(^ase. 

 It is stated that Susserin brings about a cure for hog cholera in many 

 cases, and that when inoculated for protective purposes an effective 

 immunity is produced. The use of attenuated pure cultures of hog- 

 cholera })acillus for producing immunity against the disease is safe 

 only in the hands of trained veterinarians. The substance known as 

 Porcosan has been plac(^d on the market with claims for its power in 

 producing inununity against hog cholera. It was found, however, to 

 contain living hog-cholera bacilli, and is therefore not to be recom- 

 mended. 



