82 EXPERIMENT STATION EECOKD. 



t:iiu iudividuals owing to mass infection, it may assume a fatal character. 

 The pruritus might be explained either by the toxin of the sarcoeyst (' sar- 

 cocystiue ' is the only toxin so far isolated from a protozoan) acting on the 

 central nervous system, or by the presence of the cysts in the muscle fibers 

 causing a constant stimulation of the reflex, or by their presence causing an 

 uneasiness in the muscle and inducing the animal to rub." 



What is the antigen responsible for the antibodies in Dorset-Niles semm? 

 W. GiLTNER {Michigan Sta. Tech. Bui. 13, pp. 3-16). — Aside from the fact that 

 the Dorset-Niles serum has been shown to possess protective powers against hog 

 cholera, it has not been demonstrated to contain antibodies. It has been 

 previously studied with reference to its agglutinative action on Bacillus cholerw 

 suis (E. S. It., 26, p. TS5), and although this bacillus is not considered the 

 etiologic factor in the disease, it has been shown that there are protective sub- 

 stances present in the serum against virulent cultures of this organism. Conse- 

 quently this blood is supposed to contain frequently both B. cholerce suis and 

 the filterable virus, probably 2 distinct antigens. 



In the experiments now reported, " 3 pigs were hyperimmunized by injections 

 of (a) i>. cholerw suis mixed with pig blood free of the filterable virus, (b) 

 pure cultures of B. cholerw suis, and (c) the filtered virus free of B. cholerce 

 suis, respectively. The serum from the pig hyperimmunized with B. cholerce 

 suis mixed with blood protected a 20-lb. pig in 20 cc. dose, and a 25-lb. pig in 

 25 cc. dose. This serum also agglutinated B. cholera; suis at a dilution of 

 1 : 12,500. The serum from the pig hyperimmunized with pure culture.^ of B. 

 cholerw suis furnished no protection to a 15-lb. pig in doses of 20 cc. This 

 serum agghitinated B. cholerw suis when diluted 1 : 500,000. The pig hyper- 

 immunized with the filtered virus, free of B. cholerw suis, furnished a serum 

 capable of protecting a 17-lb. pig in 10 cc. dose against the filtered virus, and 

 an 18-lb. pig in 15 cc. dose against the unfiltered virus. This serum also agglu- 

 tinated B. cholerw suis when diluted 1 : 8,000." 



According to this, upon filtering hog-cholera serum through a Chamberland 

 filter, something is removed which has much to do with producing hog cholera. 

 Perhaps the serum is only allowed to pass through, and most of the ultra- 

 microscopic organisms are retained in the filter. Mixing the Dorset-Niles 

 serum and hog-cholera virus in vitro and incubating for 2i to 3 hours does not 

 seem to lessen the potency of the virus. There is, therefore, no indication that 

 mixing serum and virus in vitro has any advantage over the serum-simultaneous 

 method of giving these agents to pigs in immunizing against hog cholera. 



Hog cholera and its prevention, C. M. Haring {California 8ta. Circ. 89, pp. 

 Jf). — A popular account of the nature of hog cholera and how to deal with it. 



Some animal parasites of the Miami County hog, D. C. Mote {Ohio Sta. Bui. 

 256; p. 254). — An examination made of 15 hogs at time of slaughter revealed the 

 presence of lung worms, ascarids, and small round worms in the large intestine. 



The life history of Habronenia muscB, a parasite of the horse trans- 

 mitted by the house fly, B. H. Ransom {U. S. Dept. Agr., Bur. Anim. Indus. 

 Bui. 163, pp. 36, flgs. 4I). — This is a detailed rei>ort of studies, an abstract ac- 

 count of which has been previously noted (E. S. R., 26, p. 255). 



A historical discussion of the subject is followed by a report of the frequency 

 of the larval worms in flies, number of larval worms in individual flies, location 

 in the body, experiments with larvfe removed from flies, survival of larvae in 

 dead flies, escape of larvae from flies, and a detailed account of the development 

 of the parasite. 



In examinations of 137 flies for the presence of this parasite, 39, or 28 per 

 cent, were found to be infested. At Washington, D. C, 4 out of 27 examined 



