VETERINARY SCIENCE AND PRACTICE. 1085 



Bulletin 57 of the Arkansas Station (E. 8. li. , 11, pp. , 689-691). lii the 

 previous experiuKMits ho used a crude tubercular material of human 

 and bovine origin, while in the present tests pure cultures of the tuber- 

 cle bacillus from these 2 sources were used for inoculation purposes. 

 During- these experiments 10 cultures, 6 of bovine origin and -1 of 

 human origin, were employed, S or more cattle, sheep, and pigs being- 

 subjected to the test. The cultures were in all instances isolated by a 

 preliminary passage through the guinea pig. As the culture medium 

 the author used 6 per cent glycerin beef scrum, coaguliited and steril- 

 ized at temperatures from 80° to 90° C. In sheep and pigs inocula- 

 tions were made in the body cavity. In cattle the inoculations were 

 made in this manner, and also directly into the substance of the lungs. 

 Seven calves, ranging in age from 2 to 17 months, were inoculated 

 with sputum cultures, 5 in the body cavity, 1 in the lung, and 1 in the 

 trachea. None of these animals suffered from any striking impair- 

 ment of health during periods of from 5 to 18 months, when they 

 were under observation. Three failed to respond to the tuberculin 

 test, 1 gave a doubtful reaction, and 3 responded positively. The 

 reaction to the tul)erculin test disappeared in all the calves within 4^ 

 months after inoculation. In 2 cases the animals were reinoculated 

 with bovine cultures 1 year after receiving sputum cultures. Post- 

 mortem examinations showed conclusively that the numerous tubercles 

 were of recent origin, and had been caused by the recent inoculations. 

 These experiments indicated that repeated injections of tuberculin and 

 previous inoculations with sputum cultures had no imnuinizing effect, 

 and that the sputum cidtures appareixtly produced only a temporary 

 form of the disease. The author T)elieves that whatever may be 

 determined the most common means of natural infection in cattle, 

 unsanitary surroimdings are in nearly all cases of great importance. 



The author used 6 sheep in determining the effect of sputum cultures 

 on these animals. The sheep which survived were kept for about a 

 year and examined, after having given a positive reaction to tubercu- 

 lin. Similar inoculations were made on sheep with bovine cultures. 

 The results obtained from these comparative tests were similar to 

 those obtained with cattle, with the exception that the sheep exhibited 

 a rather high degree of susceptibilit}' to tuberculosis produced by 

 inoculation. 



In previous experiments on pigs, no excess of virulence of the 

 bovine tubercle over that of man was noted. In comparative tests 

 with pure cultures, the difference in the effects of the sputum and 

 bovine cultures were almost as well marked as in the case of sheep. 



The general results of these experiments may be summarized as 

 follows: Pigs, sheep, and cattle possess a varying- degree of suscepti- 

 bility to tubercle bacillus of human origin, cattle being most resistant 

 and pigs least so. In pigs only were genuine cases of chronic tuber- 

 culosis developed ))y inoculation with human tubercular material. 



