886 EXPERIMENT STATION EECORD. 



ducing blood without the serum. The authors came to the conclusion that hogs 

 immune to hog cholera may be injected with virulent blood so as to develop a 

 serum which will protect susceptible hogs. Hyperimmunization may be accom- 

 plished as well by the use of one large dose of virulent blood as by repeated in- 

 jections of small doses. The serum from naturally immune hogs is as effective 

 as that from artificially immunized animals. This serum in doses of 20 cc. pro- 

 tects susceptible hogs, weighing from 25 to 50 lbs., against a fatal dose of viru- 

 lent blood. Immunity thus produced persists for 3j months or perhaps longer. 

 Hogs vaccinated by the serum-simultaneous method do not transmit the disease 

 to other hogs unless they themselves show symptoms of illness. It is possible 

 that the serum may be used as a curative agent in the early stage of the disease. 



The determ^ination of the organism, of hog cholera by means of a study of 

 complement, A. Dedjulin {Ztschr. Infcktionskrank. u. Hi/g. Haustiere, 3 

 (1901), No. 3-J,, pp. 313-32-',). — The work of this Department and other investi- 

 gators on hog cholera is briefly reviewed. An extract was obtained from the 

 bone marrow of hogs affected with hog cholera, which was shown to contain a 

 specific receiptor which was not identical with that obtained from an extract of 

 Bacillus sitipcstifcr. The conclusion is, therefore, I'eached that the pathological 

 symptoms of hog cholera are not produced by the endotoxins of B. suipestifer 

 but by some other organism specifically distinct from this bacillus. 



The etiology of German hog cholera, K. Glasser {Deut. Tierdrztl. 

 Wchnschr., 15 (1907), Xos. J/',, pp. 617-623; 45, pp. 629-636).— In the experiments 

 reported by the author it was impossible to produce hog cholera by the use of 

 germ-free filtrates obtained from mixed infection of hog cholera and swine 

 plague, chronic cases of hog cholera, or acute cases of the same disease. In- 

 jections of filtrates gave similar negative results in the case of rabbits. On the 

 other hand, when hog-cholera bacilli were fed to rabbits or hogs, typical cases 

 of the disease were produced. The conclusion is reached that in Germany the 

 only cause of hog cholera is Bacillus suipestifer. 



The etiology and control of German hog cholera, Uhlenhuth (Berlin. 

 Tierdrztl. Wchnschr., 1907, A'o. 44, pp. 783-790). — The author has demonstrated 

 that filtered virus obtained from cases of hog cholera produces acute cases of the 

 disease of unusual infectiousness. It is believed, therefore, that this virus con- 

 tains a living agent which must be considered as the cause of the disease. A 

 series of experiments was carried on for the purpose of obtaining a serum 

 which would have vaccinating power. In this work horses, asses, and hogs 

 were used, but the best results were obtained by the use of an immune serum 

 obtained from hogs. Pigs treated with this immune serum remained in health 

 though exposed continuously for 10 weeks to hogs suffering from hog cholera. 

 Control pigs treated with normal serum and exposed in the same manner all 

 contracted fatal cases of hog cholera within 2 or 3 weeks. 



These experiments in immunity were carried out on the basis of the belief 

 that hog cholera is caused by a filterable virus. In the author's opinion the 

 results indicate that Bacillus suipestifer is not the cause of the disease. 



The bacilli of swine erysipelas in decomposing organs, L. Opalka (Ztschr. 

 Infcktionskrank. u. Hyg. Huusiicrc, 3 (1907), Ao. 3-4, pp. 349-353). — An exami- 

 nation was made of the kidneys, spleen, and skin of mice which had previously 

 been inoculated with this disease. It was found that these organs may coritain 

 the bacilli of swine erj'sipelas in stainable condition. The virulence of the 

 organisms gradually diminishes and the bacilli may be identified by culture on 

 agar and by inoculation experiments. 



Do the bacilli of swine erysipelas pass through the normal udder of inocu- 

 lated cows? (). SCHREII3ER luid K. Xei'mann [Ztsclir. Fleisvli u. Milchhyg., 18 

 (1907), No. 2, pp. 57, 58). — Cows are used to a considerable extent in the prepa- 



