BACILLUS OF TUBERCULOSIS. 275 



death at the end of several weeks or months. Subcuta- 

 neous inoculations are less effective, and in small doses 

 do not always kill. Intravenous and intraperitoneal 

 iujections usually produce general tuberculosis and 

 death at the end of a few weeks. The tubercles in 

 rabbits are smaller, as a rule, and the spleen and liver 

 not so much enlarged as in guinea-pigs, but the kidneys 

 not infrequently contain nodules of the size of a pea. 



Of other susceptible animals, field-mice and cats 

 are readily infected by artificial inoculations of tuber- 

 culous material ; rats, white mice, and dogs only 

 when very large doses are given. All these animals 

 present the anatomical lesions of miliary tuberculosis. 

 Bollinger has produced intestinal tuberculosis in calves 

 by inoculating them with material taken from a tuber- 

 culous man. Canaries are also susceptible to inocula- 

 tions of the tubercle bacillus; but not sparrows. Cold- 

 blooded animals of various kinds, according to the 

 experiments of Koch, are immune, unless, as recently 

 demonstrated, the bacilli are first slowly accustomed 

 to growth at low temperatures. Fowls and pigeons 

 are only slightly susceptible to the bacillus derived 

 from man. Among the larger birds, parrots alone 

 would seem to be clearly susceptible. 



Beside the artificial modes of infection already re- 

 ferred to, tuberculosis may be caused in animals by 

 feeding them with tuberculous material. In this case 

 evidence of infection is usually shown in the mesenteric 

 glands before the intestinal walls are affected. Zagari 

 records some experiments in which tubercle bacilli fed 

 to dogs (one of the less susceptible animals) were ab- 

 sorbed by the mucous membranes of the intestines, and 

 thus reached the internal organs without producing any 



