560 FRAGMENTS OP SCIENCE. 
received the name of pebrine, was the product of a parasite 
which first took possession of the intestinal canal of the 
silk-worm, spread throughout its body, and filled the sack 
which ought to contain the viscid matter of the silk. 
Thus smitten, the worm would go automatically through 
the process of spinning when it had nothing to spin. Pas- 
teur followed this parasitic destroyer from year to year, 
and led by his singular power of combining facts with the 
logic of facts, discovered eventually the precise phase in 
the development of the insect when the disease which 
assailed it could with certainty be stamped out. Pasteur's 
devotion to this inquiry cost him dear. He restored to 
France her silk husbandry, rescued thousands of her 
population from ruin, set the looms of Italy also to work, 
but emerged from his labors with one of his sides per- 
manently paralyzed. His last investigation is embodied in 
a work entitled "Studies on Beer," in which he describes 
a method of rendering beer permanently unchangeable. 
That method is not so simple as those found eifectual with 
wine and vinegar, but the principles which it involves are 
sure to receive extensive application at some future day. 
There are other reflections connected with this subject 
which, even were they now passed over without remark, 
would sooner or later occur to every thoughtful mind in 
this assembly. I have spoken of the floating dust of the 
air, of the means of rendering it visible, and of the perfect 
immunity from putrefaction which accompanies the contact 
of germless infusions and moteless air. Consider the woes 
which these wafted particles, during historic and pre-his- 
toricages, have inflicted on mankind; consider the loss of life 
in hospitals from putrefying wounds; consider the loss in 
places where there are plenty of wounds, but no hospitals, 
and in the ages before hospitals were any where founded; con- 
sider the slaughter which has hitherto followed that of the 
battlefield, when those bacterial destroyers are let loose, 
often producing a mortality far greater than that of the 
battle itself; add to this the other conception that in times of 
epidemic disease the selfsame floating matter has frequently, 
if not always, mingled with it the special germs which pro- 
duce the epidemic, being thus enabled to sow pestilence and 
death over nations and continents consider all this, and 
you will come with me to the conclusion that all the havoc 
of war, ten times multiplied, would be evanescent if com- 
pared with the ravages due to atmospheric dust. 
