502 ARMAND RUFFER. 
disappearing after five to seven days only. Now, M. 
Tchistowitch! has recently shown that when harmless micro- 
organisms are injected into the trachea, the phagocytes of the 
lungs take them into their interior, kill and digest them; 
whilst pathogenic bacilli, such as those of the cholera of fowl], 
force their way between the cells, pass into the general circu- 
lation, and multiplying greatly, finally kill the animal. We 
may suppose, therefore, that as long as the lungs are in their 
normal state their phagocytes are able to kill and digest the 
Bacillus pyocyaneus, but that the same cells are unable to 
fulfil their task when the nerve is cut. 
M. Pasteur many years ago showed the influence of cold in 
the production of an infectious disease. 
The struggle between micro-organisms and the animal cells 
is a physiological process always going on in the tonsils, the 
microphages and macrophages being victorious in the healthy 
animal. If these structures are weakened.from any cause, e.g. 
over-fatigue, cold, nervous shock, a local disease follows the 
multiplication of micro-organisms in the tonsils. An increased 
emigration of phagocytes may limit the process to the tonsils 
even then, or the micro-organisms may break through the 
barrier of these cells, invade the animal body, and the disease 
become a general one. 
The same struggle goes on in the healthy Peyer’s patches like- 
wise, and the presence of microbes in the normal structure ac- 
counts for the fact that infectious processesin the intestines begin, 
as a rule, in these lymphoid tissues. Hereagain some pathogenic 
organisms are often present, others constantly so, but their 
mere presence is not sufficient to set up disease. The septic 
vibrio in the rabbit’s intestine does that animal no harm; the 
bacilli of tubercle and typhoid, which most men ingest at some 
time or other, prove innocuous asa rule, that is as long as men 
are healthy. But here, as in the tonsils, over-fatigue, deficient 
food or oxygen may weaken the animal’s resistance, that is, 
1 Tchistowitch. At the time of writing M. Tchistowitch had not 
published his paper. Thanks to his kindness I was able to see his very in- 
teresting preparations at the Pasteur Institute in Paris. 
