560 
JOHN FORBES. 
Besides this inherited weakness of the system, this so- 
called “ tubercular diathesis,” there are other influences 
which may reduce the organism to the state suitable for the 
propagation of the bacillus. 
In cattle the most potent influences are overcrowding, 
and excessive milking, a very common occurrence in city 
dairies; and let me impress upon you the fact that a phthis¬ 
ical attendant of dairy cattle may be a source of danger, not 
only to the health of the cattle, but to the public who con¬ 
sume the product of that particular dairy. 
The city that does not have a scientific supervision of the 
source of its milk supply lacks in its duty to its citizens. 
There are cases on record of a phthisical patient which im¬ 
parted the disease to chickens in the yard, who devoured his 
sputa; of another who inflicted the disease upon two pet 
dogs in succession, and would have given it to the third had 
the patient not died before it could be effected. If that can 
be said of these animals, might not the same be true in re¬ 
gard to cattle ? Even if it were not, there is always the dan¬ 
ger of the milk becoming infected through the dried sputa 
of the diseased attendant, and we all know that milk is one 
of the most frequent habitats of disease germs. 
We have seen that the bacillus must find entrance to the 
body before we can have tuberculosis, and it may be of inter¬ 
est to us to know how it gains access. 
Infection through wounds has often been recorded, and 
in such cases the process of repair is retarded, the infective 
process spreads to the adjacent glands, and ultimately results 
in general tuberculosis. Fraenkel relates that this had taken 
place in surgical operations. 
Through the alimentar}^ canal infection often takes place 
by the ingestion of contaminated food. Being able to resist 
the action of the gastric juice, the bacilli readily gains en¬ 
trance to the abdominal glands. 
The most frequent point of entrance of the bacillus is the 
respiratory tract. As with the other methods of infection 
the same conditions do not prevail in this instance. 
The substance that contains the bacilli must first dry up 
