852 
REMARKS ON MICRO-ORGANISMS. 
abrasion of the epithelium in the mouth or pharynx is probably 
the channel; and this view is confirmed by the fact that a 
similar affection of the lymphatic glands, together with other 
symptoms of the disease, is produced by inoculating the 
chicken in the mouth; and further, by the circumstance that 
such chickens as fail to take the disease when fed with the 
infected food are liable to it when inoculated, implying that 
it was merely some accidental circumstance which secured 
their previous immunity. This disease has been made the 
subject of special investigation by M. Pasteur. He found 
that the micro-organism could be readily cultivated outside 
the body of the fowl. It was, indeed, somewhat particular 
as regards the fluid in which it would grow; thus, yeast-water, 
in which the Bacillus anthracis grows readily, proved an un¬ 
suitable medium for this organism, but it grew luxuriantly in 
chicken-broth, and, indeed, in infusion of other kinds of 
meat; but chicken-broth proved peculiarly convenient for the 
purpose. M. Pasteur has been so kind as to send me some 
tubes in which the organism has been cultivated, and a drop 
of the liquid has been placed under a microscope on the table. 
It will be seen that the organism is a minute form of bacterium, 
oval-shaped,tendingto multiplication by transverse constriction, 
and very frequently seen in pairs, and occasionally in chains. 
Its transverse diameter is from 1-50,OOOth to 1-25,000th of an 
inch; so that it resembles very closely the Bacterium lactis 
(see d in the woodcut taken from a camera lucida sketch of 
the organism sent by M. Pasteur). So far as I am aware 
this is the first time this bacterium has been shown in this 
country. Now, it was found by Pasteur that the organism 
could be produced in chicken-broth in any number of successive 
cultivations, and to the last retain its full virulence; so that, 
if a healthy chicken were inoculated with it, the fatal disease 
was produced as surely as by inoculation with the blood of a 
fowl that had died of the complaint. This was pretty con¬ 
clusive evidence that the organism was the cause of the 
disease, and that it constituted the true infective element; 
because any other material that might be supposed to accom¬ 
pany it in the blood of the diseased animal must have been 
got rid of by the successive cultivations in chicken-broth. 
The growth of the organism occasions no putrefaction in 
the liquid, so that this is a good example of a bacterium which 
is most destructive as a disease, but which is at the same time 
entirely destitute of septic property, in the primitive sense of 
that term as equivalent to putrefactive. After the bacterium 
has grown for a certain time in a given portion of chicken- 
broth, it ceases to develop further; and when this is the case. 
