246 A MANUAL OF BACTERIOLOGY 



bacilli enter the body, viz., by pulmonary inhala- 

 tion (atmospheric infection), swallowing (enteric 

 infection), direct inoculation, and heredity, (a) 

 Inhalaton is the commonest mode of infection. 

 Koch and numerous other observers have proved 

 that animals, after a few inhalations of phthisical 

 sputum, disseminated in a spray, readily become 

 infected with tuberculosis. Eansome l has isolated 

 the tubercle bacilli from the breath of patients 

 suffering from advanced phthisis ; and the author 2 

 has confirmed Kansome's investigations ; therefore 

 it will be seen that tuberculosis may pass from 

 husband to wife, and vice versd ; and it may also 

 affect members of the same family, not because of 

 any hereditary taint, but through the simple fact of 

 close companionship. 3 The sputa or expectorations 

 of phthisical patients are highly infectious, even 

 after being desiccated for several months. Bacillus 

 tuberculosis is often to be found in places lived in 

 by consumptives ; and Prausnitz has lately collected 

 the dust in various compartments of trains which 

 often convey patients from Berlin to Meran, and 

 inoculated a number of guinea-pigs with it. Two, 

 out of five compartments so examined, were found 

 to contain the bacillus; the dust of one rendered 

 three out of four guinea-pigs tuberculous, while 

 that of the other compartment infected two of these 



1 Proc. Roy. Soc., 1882. 



2 Proc. Roy. Soc. Edinburgh, vol. xvii. p. 268. 



3 See Weber's book, The Gommunicability of Consumption 

 from Husband to Wife ; and Heron's Evidences of the Communi- 

 cability of Consumption. 



