Bacilli Resembling the Tubercle Bacillus 691 



characteristic of the avian bacillus, which grows upon ordinary 

 agar-agar and bouillon prepared without glycerin. 



The growth also lacks the dry quality characteristic of cultures 

 of the human and bovine bacilli. Old cultures of the bacillus of 

 fowl tuberculosis turn slightly yellow. 



Thermic Sensitivity. — The bacillus also differs in its thermic 

 sensitivity and will grow at 42° to 4S°C. quite as well as at 37^C., 

 while the growth of the human and mammalian bacilli ceases at 

 42°C. Moreover, growth at 43°C. does not attenuate its virulence. 

 The thermal deathpoint is 7o°C. Upon culture-media it is said to 

 retain its virulence as long as two years. 



Pathogenesis.^ — Birds are the most susceptible animals for 

 experimental inoculation, the embryos and young being more sus- 

 ceptible than the adults. Artificial inoculation can be made in the 

 subcutaneous tissue, in the trachea, and in the veins; never through 

 the intestine. After inoculation the birds die in from one to seven 

 months. The chief seat of the disease is the liver, where cellular 

 (lymphocytic) nodes, lacking the central coagulation and the giant- 

 cell formation of mammalian tuberculosis, and enormously rich in 

 bacilli, are found. The disease never begins in the lungs, and the 

 fowls that are diseased never show bacilli in the sputum or in the 

 dung. 



Guinea-pigs are quite immune, or after inoculation develop cheesy 

 nodes, but do not die. 



Rabbits are easily infected, an abscess forming at the seat of 

 inoculation, nodules forming later in the lungs, so that the dis- 

 tribution is quite different from that seen in birds. It is possible 

 that the avian bacillus occasionally infects man. 



The possibility that this bacillus is derived from the same stock 

 as the tubercle bacillus is strengthened by the experiments of 

 Fermi and Salsano,* who succeeded in increasing its virulence until 

 it became fatal to guinea-pigs, by adding glucose and lactic acid to 

 the cultures inoculated. 



FISH TUBERCULOSIS 



Dubarre and Terrej isolated a bacillus having the tinctorial and morphologic 

 characteristics of the tubercle bacillus from carp suffering from a tubercle-like 

 affection. In respect to cultivation, however, it was unlike the tubercle bacillus, 

 growing readily upon simple culture-media at 15° to 30°C., and not at 37°C. 



Weber and TaubeJ found the same organism, or what seemed to be the same 

 organism, in mud and in a healthy frog. 



BACILLI RESEMBLING THE TUBERCLE BACILLUS 



It is not improbable that the bacilli of human, bovine, and avian tuberculosis 

 are closely related to one another, and, together with a few other micro-organisms 

 of similar morphology and staining peculiarities, have a common ancestry 



* "Centralbl. f. Bakt.," etc., xii, 750. 



t "Compt. rendu de la Soc. de Biol, de Paris," 1897, 446. 



X "Tuberkulose Arbeiten aus dem Kaiserlichen Gesundheitsamte," 1905. 



