1130 EXPERIMENT STATION RECORD. 



A third race of tubercle bacilli was obtained from Professor Arloing and had been 

 rendered homogeneous according to his method. This culture was also tested on 

 mice, guinea pigs, rabbits, goats, horses, and cattle and was found to differ in a pro- 

 nounced manner from other tubercle cultures of human origin. It was the least 

 virulent of all tubercle bacilli obtained from man. In rabbits and horses it pro- 

 duced slight symptoms of pneumonia, but when used in small doses the inoculated 

 animals soon recovered. 



Detailed notes are also given on cultures obtained from cattle and on the results of 

 inoculation experiments with these cultures. Considerable difference in virulence 

 was obtained between different cultures, but as a rule guinea pigs were killed within 

 4 to 8 days by intraperitoneal inoculation with bovine tubercle bacilli. The lesions 

 produced in guinea pigs from certain bovine cultures were very similar to those 

 caused by tubercle bacilli from birds. 



Numerous experiments were made with tubercle bacilli obtained from birds, and 

 during these experiments quite striking differences in virulence were observed, as in 

 the case of tubercle bacilli obtained from man and animals. Cultures obtained from 

 birds were characterized by their high virulence toward experimental animals, espe- 

 cially toward cattle. In guinea pigs phenomena of intoxication were sometimes 

 pronounced, while the formation of tubercles was less striking. The power of pro- 

 ducing true tubercles in guinea pigs was greatly accentuated by the passage of the 

 avian tubercle bacilli through mammals. 



The intermediary body of the tubercle bacillus, Dembinski ( Compt. Rend. Sue. 

 Biol. [Paris], 57 {1904), No. ,34, pp. 502-504)— -The author studied the behavior of 

 the intermediary body in the serum of rabbits and pigeons inoculated with tubercle 

 bacilli of human and avian origin. 



The injection of human tubercle bacilli into rabbits or pigeons did not cause the 

 formation of the intermediary body, but a similar injection of avian tubercle bacilli, 

 on the contrary, brought about the appearance of this body. The production of the 

 intermediary body therefore appears to depend, not upon the greater or less resist- 

 ance of the animal toward tubercle bacilli, but upon the race of tubercle bacilli used 

 in the experiments. 



The intermediary body exhibits a similar action toward tubercle bacilli, whether 

 living or dead and whether of human or avian origin. The injection of experimental 

 animals with dead human or avian tubercle bacilli does not cause the production of 

 the intermediary body in the blood. 



The histogenesis of the tubercle, J. Miller (Jour, l'ath. and Bad., 10 (1904), 

 No. 1, pp. 1-49, ]>ls. 4)-- — The observations reported in this paper were chiefly con- 

 fined to a study of the development of tubercles in the liver of rabbits. The anatomy 

 of this organ is carefully described with reference to its relationship to the progress 

 of tuberculosis. 



The liver was inoculated by injecting tubercle bacilli into a branch of the mesen- 

 teric vein. The microscopic changes produced in the liver of rabbits as the result of 

 the infection of human tubercle bacilli were described in great detail. It appears 

 that the tubercle bacillus causes the formation of the tubercle partly as a result of 

 irritation like that produced by other foreign bodies and partly as the result of the 

 presence of a specific toxin which causes caseation in the surrounding tissue. The 

 tubercle bacillus is distinguished from most related organisms by its exceedingly 

 slow development. 



The aggregation of cells which constitutes the tubercle is considered to be due to 

 a process of phagocyt< >sis. ( riant cells, epithelioid cells, and lymphocytes are believed 

 to be simply stages in the development of a phagocyte. The mononuclear cells of 

 the blood play an important role during the whole process of formation of the tuber- 

 cle. In the early stages of the process giant cells result from a fusion of several 



