380 EXPERIMENT STATION RECORD. 



tions of surra of India and mal de caderas were car-able of infecting mice 

 when introduced as early as 24 hours after the medicament. 



" In prophylactic and immunity experiments where infection followed by 

 spontaneous recovery took place, the number of days intervening between the 

 appearance of the parasites and their disappearance usually varied directly 

 with the number of days separating the treatment and the test. From this it 

 seems that the stronger the influence of the unexcreted medicament, the more 

 quickly the parasites are banished from the blood. The strength of the im- 

 munity was often sutEcient to prevent infection completely in the tests made 

 comparatively soon after treatment. Such an immunity was secured in mice 

 cured of surra of India, surra of Mauritius, mal de caderas, nagana, and a 

 toluidin blue resistant nagana strain. 



"At times, varying degrees of hypersensitiveuess to infection were noted. . . . 

 It is of interest to note that in 3 of these 5 instances of hypersensitiveuess, the 

 surra of Mauritius that infected had been passed through one or more guinea 

 pigs. When a double infection was treated, a double immunity was secured. 

 By means of the immunity reaction it was apparently possible in a number of 

 instances to separate in purity organisms that had been mixed in vitro." 



A new method for immunizing' against trypanosome diseases, C. Schil- 

 ling {Deut. Med. Wclinschr., 38 {1912), No. 1, pp. 18, 14). — The method used is 

 as follows : 



Rats at the height of infection, that is, when the blood contains a large 

 amount of trypanosomes, are bled into bouillon containing 2 per cent of sodium 

 citrate. In this solution the trypanosomes will live for several days, it dif- 

 fering in this respect from sodium chlorid solutions. After centrifuging the 

 mixture, the supernatant cloudy fluid is pipetted off, and an equivaleut amount 

 of bouillon containing 1 part to 700 of tartar emetic added to the residue. After 

 centrifuging in an electric apparatus, a suspension is made of the residue in 

 bouillon, and from 0.5 to 2 cc. injected into rats. 



By this process the incubation period of the strain employed, nagana, was 

 increased from 24 hours to from 4 to 27 days. In a majority of the animals 

 a single injection will render the animals nonreceptive to later infection. In a 

 few animals the disease recurred in a few days. The serum from such im- 

 mune rats protects mice against a simultaneous infection with nagana trypano- 

 somes. Dogs are better fitted than rats for such tests, and a single injection 

 of trypanosomes so prepared will incite the formation of antibodies which can 

 be detected by the complement fixation method. 



Only 1 test was conducted with a horse, and the results were the same as 

 those given by the mouse. The work with the horse, however, will be 

 continued. 



About a new culture medium, for the rapid development of the tubercle 

 bacillus, G. Valletti (Centhl. Bakt. [etc.], 1. Aht., Orig., 68 {1913), A^o. 2, 

 pp. 239-2Jfl). — After pointing out that very few text-books mention milk as a 

 possible medium for cultivating the tubercle bacillus, the author recommends 

 a culture medium composed of bouillon agar with sodium chlorid but without 

 glycerin, to which is added 2 cc. of serum from cow's milk. The serum is pre- 

 pared by adding a few drops of acetic acid to milk and then boiling. 



In this medium the bovine tubercle bacillus showed a marked development in 

 1 to li days' post inoculation, whereas control cultures on substrats containing 

 glycerin, blood serum, etc., showed not the slightest growth. The human type 

 of bacillus did not develop on this medium, but whether the bovine type was 

 selective for the medium has not been established. The author intends to con- 

 duct some tests with human milk sera to determine this point. 



