146 APPLIED BACTERIOLOGY 



to say, are born of those already weakened by the disease, 

 and have, perhaps, been brought up in an atmosphere 

 teeming with the specific virus — it does not seem hard to 

 account for the run of the disease in families, or, as is 

 sometimes noticed, in particular habitations. The warty 

 excrescences which sometimes follow post-mortem wounds, 

 and are apt to appear on the hands of those often occupied 

 in handling dead bodies (dissecting porters' warts), are of 

 tubercular origin. Fortunately, in man these lesions rarely 

 spread, and remain local or heal altogether, while in sus- 

 ceptible animals (rats, mice, guinea-pigs) an inoculation 

 produces general tuberculosis in the course of a few 

 weeks. 



In some cases of leprosy the tubercle bacillus is associated 

 with the Bacillus leprae, while lupus, scrofula, and possibly 

 scurvy, are all due to the Bacillus tuberculosis. 



The partial immunity enjoyed by the Jews is remarkable, 

 nor has any sufficient reason yet been assigned for it ; it is 

 perhaps partly due to the care taken of their meat-supply, 

 and partly to the fact that much of their food is cooked in 

 oil or fat. 



Dr. Theodore Williams has proved that tubercle bacilli 

 are present in the atmosphere of a hospital for phthisical 

 patients by suspending glass plates covered with glycerine 

 in an extraction-shaft of the Brompton Hospital. Other 

 observers have demonstrated the presence of the bacillus 

 in the dust of rooms occupied by phthisical patients. 

 In health-resorts much frequented by phthisical patients, 

 the chances of infection by inspiration of tubercle-containing 

 dust are considerable, and it often happens that thoughtless 

 or ignorant persons needlessly expose themselves to the risk 

 of tubercular infection. Medical men should make a point 

 of impressing on phthisical patients and their friends the 

 infective character of the disease, which is not fully recog- 



