384 EXPERIMENT STATION EECOED. 



sitional form. Its morphological variation from iSf. siiis, as found in ulcers and 

 local foci, may be due to the unfavorable action of blood as a medium or to its 

 natural processes as a part of the life cycle of the species. 



" ;Sf. siiis is an obligatory anaerobic organism and usually requires several 

 weeks' incubation for growth to take place on artificial culture medium. It 

 may be transferred from generation to generation on artificial culture medium. 

 Cultures containing the organism in the form of granules and spirochetes may 

 be passed through bacteria-proof filters and the spirochetes removed, the few 

 small granules which pass through being capable of producing hog cholera or 

 resistance to the disease. 



" 8. stiis Is capable of producing typical hog cholera when injected into 

 healthy hogs. This is true not alone of contaminated cultures made directly 

 from the intestinal ulcers of cholera hogs; second and third generations on 

 artificial culture media, containing the 8. suis, as well as the Berkfeld filtrates 

 of the same transfers, are capable of producing hog cholera and marked reac- 

 tions, which confer more or less protection against the disease. The patho- 

 genicity of these cultures does not appear to be due to the passage of an un- 

 known * invisible micro-organism' which is finally transmitted to healthy hogs 

 by inoculation. Control experiments tend to show that the pathogenicity of the 

 cultures of 8. stiis is due to the species itself in the form of spirochetes or 

 granules. 



" Finally, in those hogs which received the disease from cultures of 8. suis, 

 the organism is present in the Intestinal lesions or local external lesions, as 

 demonstrated by the dark field examination. 



"As the above results have practically fulfilled Koch's laws, in so far as it is 

 possible with an organism possessing the biological characteristics of spiro- 

 chetes, [the authors believe] it may logically be concluded that /Sf. suis is more 

 nearly established as the specific cause of hog cholera than any other known 

 organism." 



Cultivating" the virus of hog cholera, W. Pfeiles and W. Lentz {Berlin. 

 Tierdrztl. Wchnschr., 29 (1913), ^^o. 39, pp. 689-692) .—The virus used in these 

 experiments was obtained from the organs of infected hogs, and filtered in 

 order to render it sterile so far as visible organisms were concerned. A loopful 

 was then tested with regard to its infectivity and another loopful was sown 

 on a nutrient medium. In most cases no hog cholera was produced before 

 cultivation in the medium. After cultivation a loopful of the culture was 

 transferred into another flask containing nutrient medium and at the same 

 time a loopful or a fraction thereof was given subcutaneously to shoats. The 

 cultures were transplanted in the manner described until a dilution correspond- 

 ing to 1 : 200,000,000 loopfuls was obtained. In most cases hog cholera was pro- 

 duced with every dilution (after cultivation) and almost every form of the 

 disease could be noted. 



It was also possible to cause the disease with an organ filtrate of the animals 

 infected with the cultivated virus, and in some instances infection was produced 

 by simple cohabitation and by feeding a 1 : 100,000,000 dilution. 



A note on kidney worm infestation of swine as shown post-mortem at the 

 Manila matadero, R. W. Newcomb {Philippine Ag?\ Rev. lEnglish Ed.}, 6 (1913), 

 2Vo. 8, pp. 399, 400). — An investigation was made by the author of the occurrence 

 of 8tep1ianurus dentatus in native hogs killed at the Manila matadero, which 

 at the same time permitted the gathering of information regarding its distri- 

 bution in the southern part of central Luzon. In all some 2,000 hogs were 

 examined and nearly 50 per cent found to be infested. 



" The parasites are most commonly found in the fatty tissue posterior to the 

 kidneys, though they may be found in the hilum of the kidney or even in the 



