Auc»., 1889. 
president's address. 
181 
equally with the chyle, by the lacteal vessels, and thus carried 
into the general circulation. On the contrary, there is distinct 
evidence that they are so carried. The lymphatic tissue of 
the Peyer’s glands of the intestine of perfectly healthy rabbits 
has been shown to contain numbers of Bacilli, and they are 
sometimes found in the amoeboid cells of the blood. But 
there they are already dead ; the putrefactive Bacteria of the 
intestine must be killed, nearly immediately, by contact with 
living cells. 
This question of the fate of microbes in the blood of warm¬ 
blooded animals has been carefully investigated. Living 
saprophytic Bacteria of the following species:— Bacillus 
subtilis, B. acidi - lactici, Micrococcus aquatilis , Spirillum 
tyrogenum, were injected into the blood, and not a trace was 
visible after three hours. Even those which are pathogenic 
to man (but not to the animal experimented upon) disappeared 
in from three to four and a half hours, as e.g ., Micrococcus 
tetraqonus , Bacillus typhi - abdominalis, Spirillum cholerce- 
asiatica , and Streptococcus pyogenes. It was proved also that 
their disappearance was not effected by excretion, either 
through the kidneys or the intestine, and the conclusion 
arrived at was that they were destroyed by contact with the 
endothelial cells. 
We may compare the horde of microbes to an invading 
army of Goths or Vandals. The cells of the living tissue 
wage war against the intruders to defend their homes, and, if 
healthy, are always victorious. But if weakened from any 
cause they may succumb, and then the invading regiments 
seize upon the dead cell, multiply, and devour it ,and make of 
it a vantage ground for attacking the neighbouring cells. 
These dead cells may be absorbed into the circulation, and the 
Bacteria enclosed within them may be sufficiently protected 
from the hostile action of the blood to remain alive for some 
time; and if, during this time, they are carried to any part 
where disintegration or inflammation has set in, they may 
settle there, and find an appropriate nidus for their growth. 
We can thus account for the presence of certain kinds of 
microbes in diseased tissues within the body to which they 
could not have had, directly, any means of access. 
But if the microbe which gains entrance to the body is a 
pathogenic organism to the animal in question, of course, the 
changes which take place are of a different character. 
Various kinds of bacterian diseases are produced, but into this 
topic, though it is of unsurpassable interest, I do not intend 
to enter, having considered the subject from the point of view, 
not of a physician, but of a cryptogamic botanist. 
