888 EXPERIMENT STATION RECORD. [Vol.38 



and a discussion of the tuberculiu reaction. An inquiry into the cases wliere 

 tuberculin has failed to produce a reaction on tuberculous animals has shown 

 that the failure may be attributed to one or more of the following causes: (1) 

 The use of strains of tubercle bacilli which do not make an efficient tuberculin, 

 (2) the use of cultures of the bacilli which are not properly grown and do nor 

 contain a sufficient quantity of the specific protein to enable it to cause a reac- 

 tion, (3) the interpretation of the manifestations following the use of tuber- 

 culin not made in accordance with the laws governing the reaction between it 

 and the products of tuberculous lesions in the living animals, (4) the applica- 

 tion of tuberculin in the period of incubation, (5) the tuberculous lesions being 

 arrested, healed, encapsulated, or very extensive, and (6) repeated administra- 

 tions of tuberculin resulting in the failure of the reaction after one or more 

 injections. In the opinion of the author subcutaneous injection has been more 

 satisfactory than other methods of administering tuberculin. 



The biological behavior of Piroplasma bigeminum in cows in Eritrea. — 

 The variety acquired in the practice of serum vaccination against rinder- 

 pest, G. Di DoMizio {Mod. Zooiatro, Parte Sci., 28 (1911), Nos. 10, pp. 232- 

 236, fig. 1; 11, pp. 2Jf7-259). — P. bigeminum in Eritrea is so widespread that 

 practically all cows are afflicted with it at some period of their lives. As a 

 latent infection it may not be detected by itself either clinically or microscopi- 

 cally, but it is very easily detected in connection with rinderpest. An animal 

 whose resistance is weakened by rinderpest is more susceptible to P. bigeminum, 

 which is often present in the blood used for inoculation against rinderpest. 

 For this reason the author recommends that in serum vaccination against rinder- 

 pest in Eritrea great care should be taken regarding the purity of the serum 

 in order to have it as free as possible from the Piroplasma. This can best be 

 accomplished by taking the serum on the fourth or fifth day of the disease at 

 which time the symptoms of rinderpest alone are present, the circulating blood 

 containing active rinderpest virus but with no Piroplasma or in such small 

 quantities that it can not be detected in microscopic examination. The serum 

 should not be taken on the sixth or seventh day of the illness, because the 

 virulence of the virus is more attenuated and because the P. bigeminum is 

 probably present in greater numbers and in a more virulent form. 



A bacteriological report in regard to hog cholera, G. F. Gardenghi {Clin. 

 Vet. [Milan'i, Rass. Pol. Sanit. e Ig., J,l {1918), No. If, pp. 84-88).— A typical 

 case of hog cholera is reported with post-mortem findings and a bacteriological 

 study of the filterable virus obtained from the animal. 



The results led to the conclusion that the Voldagsen strain of paratyphoid 

 B can be found associated with filterable virus in hog cholera. 



Fundamental principles governing the control of hog cholera, D. F. Lvckey 

 {Amer. Jour. Vet. Med., 13 {1918}, No. 4, pp. 157-160, 200).— The principles dis- 

 cussed are more thorough and efficient organization, attention to the sources of 

 infection, more stringent quarantine regulations, and laws forbidding the sale 

 of hogs affected with any disease and prohibiting vaccination except by graduate 

 veterinarians. 



Statistics on the use of hog cholera antisertim and hog cholera virus, C G. 

 Cole {Amcr. Jour. Vet. Med., 13 {1918), No. 4, pp. 173, 77^/).— During the year 

 3917, 16.7 per cent of all the hogs in Iowa were immunized. The average per- 

 centage- of losses from the use of the simultaneous method in healthy herds 

 over a period of five years was 2.1, the loss in 1917 being only 0.7 per cent. A 

 report on 264,307 hogs, consisting of 92,943 sick or exposed and 171,424 healthy 

 hogs, shows a loss of 2.1 per cant of healthy and 15.5 per cent of sick hogs. 

 Of the hogs actually sick when treated, a recovery of 34.1 per cent is shown 

 by the use of the serum-alone method against 29 per cent by the use of the 



