TUBERCULAR INVASION IN SWINE. 
655 
and adjacent lymph structures with no head lesions, but these 
cases form a very small per cent. In some instances where 
there has been found abdominal lesions there was also observed 
upon close examination minute tubercles in the intestinal wall, 
some located between the mucous and muscular coat, others be¬ 
tween the muscular and serous. Then, again, we find a peculiar 
condition affecting the submaxillary, bronchial, and portal 
glands and the liver, with no other visible lesions. We often 
find the pleura invaded with no lesions in the lung substance, 
and it has been noted that the tubercle appears to push out from 
the under side of the serous membrane. 
This being the fact, that the lesions in the larger per cent, of 
the cases are primarily found in the glands of the head, what con¬ 
clusion must we deduce ? That infection takes place through in¬ 
gestion, and that the microorganism gains entrance through the 
buccal mucous membrane, but how, is the question. In fact, the 
bacillus being non-motile has caused much time to be spent by 
writers in elaborating on theories as to how this end is brought 
about. 
We know that hogs eat rough substances, such as stone, coal, 
glass, and I have found, besides these, nails, staples, hair and 
other objects in stomachs examined. These sharp and rough 
or pointed bodies may lacerate the buccal mucous membrane, 
and another thing to be taken into consideration is the teething 
period in young hogs, at which time there may be abraded sur¬ 
faces ; any catarrhal or inflammatory condition which would 
cause an exfoliation of epithelia or abrasion or to so weaken the 
cells as to make entrance possible. Again, it has been demon¬ 
strated that the bacillus, which we know to be vegetable, some¬ 
times throws out prolongations (see Friedberger and Frohner’s 
“Pathology and Therapeutics of the Domestic Animals ”); might 
not the bacillus become lodged in a fold of the buccal mucous 
membrane and under favorable conditions, which would be af¬ 
forded in the mouth, that is, heat and moisture, etc., develop or 
throw out a prolongation, gradually entering between the epith¬ 
elial cells as it grows, and in this way gain entrance ? Again, the 
