VETERINARY MEDICINE. 585 



healthy animals. Of these latter 60 were given 5 cc. of protective serum sub- 

 cutaneously, the others being kept as controls. Three weeks later 7 of the 

 control animals were affected, but all those that had received a dose of serum 

 had escaped infection. In view of the fact that the immunity conferred by 

 the serum was effective for 2 to 4 weeks only, an attempt was made to pro- 

 long the period by giving an inoculation of serum and virus mixed. The 60 

 animals were therefore given 5 cc. of serum mixed with in cc. of virulent 

 pleural exudate from an experimental case. Two months later it was reported 

 that none of the protected animals had become infected, while the control ani- 

 mals had. 



"A second flock was divided into 2 lots of 100 animals each, which were 

 placed in folds about 200 yds. apart. The disease broke out in a severe form 

 in 1 of the folds, and within 3 weeks 40 of the animals were dead, and the 

 others were in a very poor condition. The flock in the second fold remained 

 free of the disease. Contagion was, however, inevitable, as the same persons 

 attended both lots of animals. The whole of the healthy batch received 5 cc. 

 of serum subcutaneously, but a week later 2 animals were found to be diseased. 

 In the author's opinion these animals were in the incubation state when the 

 serum injections were given, and the fact that they contracted the disease 

 showed that the fold was infected. The same day 50 healthy adult animals 

 in the fold were given a dose of serum and virus as in the case of the first flock 

 mentioned. At the request of the owner 10 of these animals were placed with 

 the infected batch. None of the vaccinated animals had contracted the dis- 

 ease 2 months later. Even those placed with the diseased animals had re- 

 mained free. 



"A third flock numbering 110 ewes contained 2 diseased animals. Serovac- 

 cination was practiced on the whole flock, and no fresh cases had appeared up 

 to 3 months later." 



From the experiments the author concludes that the antiagalaxia serum 

 possesses immunizing properties, but it seems to be without value when given 

 during the period of incubation or after the symptoms have appeared. Sero- 

 vaccination prolongs the immunity conferred by the serum alone, but the dura- 

 tion of the immunity so produced has not been established. It is of sufficient 

 length, however, to allow an epidemic to die out. 



Spiroclietes in hog- cholera, G. Arnheim {Ztschr. Hyg. n. Infektionskranlx., 

 76 (lOl.'f), No. 3, pp. 4'^5-437). — Hog cholera, according to this investigation, is 

 not caused by spirochetes. The findings of King, Baeslack, and Hoffmann 

 (E. S. R., 29, p. 681) are criticized on the ground that up to this time spi- 

 rochetes have not been filtered under pressure, and furthermore, that sJilvarsan. 

 a well-known spirochete poison, is not of any value in hog cholera. In the hog 

 cholera virus, however, certain transitional forms were noted. 



From the blood taken from the tails of infected hogs spirochetes were found, 

 but none were noted in the blood obtained by puncturing the heart. Spiro- 

 chetes were also noted in the intestinal tract where a slight intestinal diph- 

 theria was present. From the mesenteric lymph glands of a pig dying of hog 

 cholera and a severe intestinal diphtheria the same spirochete could be ob- 

 tained by cultivation by Schereschewsky's mixed culture method. 



The spirochetes found in hog cholera are believed to originate from the in- 

 testines. 



Hog cholera investigation, R. A. Craig (Indiana Sta. Rpt. 1913, pp. 76-79). — 

 In testing the comparative virulence of the virus in blood, urine, and filtered 

 and uufiltered salt solutions from cholera hogs, pigs w^eighing from 30 to 60 

 lbs. were injected intramuscularly. Pigs inoculated with the virus in blood 

 lived an average of 12.08 days; those with virulent salt solution, 12.92 days; 



