224 
SOCIETY MEETINGS. 
englobulated, together with its aggressor, by the larger yet less 
ambitious helper, the macrophage. These macrophages are 
large, almost indolent cells, with little power of movement, and 
stationed about the system where most needed to assist in the 
phagocytary protection. Their action in englobulating and di¬ 
gesting poisonous germs is similar to that of the microphage ; 
they are composed of fixed connective tissue cells, endothelial 
cells of vessels, cells of the spleen, bone marrow, in Peyer’s 
patches, and pulmonary alveoli. 
We are aware that germs of tuberculosis are often introduced 
into the system which find no lodgment there. Again the sys¬ 
tem may be contaminated and extensively affected from one in¬ 
troduction, and that introduction may be trivial. There are 
those cases that develop with great rapidity, while others will 
remain dormant, apparently gaining but little upon the animal 
economy. The susceptibility of the system, the extent and 
rapidity of development, depend upon the virulence of the in¬ 
fection, the extent or supply of tubercular matter, the phago- 
cytory aptitude of the cells. The latter varies greatly in differ¬ 
ent animals, and can be modified and reduced in all by poor 
sanitary surroundings and by disease. Once the animal becomes 
weakened or debilitated by disease or poor hygienic surround¬ 
ings, the germs which may be in a dormant or inactive state take 
advantage of the weakened phagocytory elements and become 
inure and active, thus overpowering a system which under 
favorable surroundings enjoyed a certain degree of immunity. 
The bacilli of tuberculosis having been absorbed with the 
ingesta and entered into active conflict with the phagocytes, 
become scattered in the deep organs throughout the abdominal 
cavity. Phagocytes charged with irritating properties usually 
make their way into the lymph channels and are carried with 
the lymph stream to the various organs. Many, no doubt, are 
carried to the liver by the portal circulation, thus giving rise 
to a possible infection of this organ in the primary stage. Even 
though they reach the liver they are not always permitted to 
establish an infection, for they are usually transported to nearby 
lymphatics for the purpose of continuing the conflict ; still this 
is not always the case, the germs may become liberated in the 
liver and gain a foothold, thereby producing a minute, circum¬ 
scribed, chronic inflammation by which process the tubercular 
nodule is developed, growing rich in giant cells with the pres¬ 
ence of more or less bacilli. 
The spleen, apparently one of the primary seats of infection 
