

MY WORK AND BACTERIOLOGY 309 
With regard to human beings exact and perfectly 
convincing evidence is almost entirely absent. 
It is well known that Behring disbelieves in this 
very commonly accepted view; and that it is 
beginning to be more generally discredited by others, 
is shown by the fact that, in a recent number of the 
British Medial Journal, the very possibility of 
such a mode of infection is questioned, as may be 
seen from the following statement (November 10, 
1906, p. 1323): “It is generally held that the peri- 
bronchial nodules frequently observed represent the 
initial lesion in pulmonary tuberculosis, and that 
these result from the direct introduction of germs 
carried in the air. On the other hand, evidence is 
not wanting that the penetration of air-borne Bacilli 
into the lungs is difficult, if not impossible.” 
And, even supposing that air-borne germs, con- 
tained in minute fragments of pulverised sputa, are 
capable of gaining access to the lungs, two other 
questions arise, to which an answer should be 
obtained : (1) Is the dried phthisical sputum a sub- 
stance easily capable of being pulverised? and (2) 
are germs contained in dried sputa, which have 
undergone pulverisation, likely to retain their activity 
and prove efficient contagia? 
Some experimental investigations in reference 
to these latter points have recently been made by 
Cadéac,! and his results are decidedly adverse to 
the still fashionable hypothesis as to the transmis- 
sion of tuberculosis by the inhalation of dust derived 
from dried sputa. Thus he found (1) from experi- 
1 Lyon Médicale, December 10, 1905. 
