522 LANCASHIRE VETERINARY MEDICAL ASSOCIATION. 
all the virulence of putrescent animal or vegetable infusions, notwith¬ 
standing that the original liquid contained only sugar ammonic tartrate 
and certain inorganic salts. Let us endeavour to realise what happens. 
We have to begin with virtually a solution of ammonic tartrate ; for it 
can be shown that it is all that is wanted at the outset. Into that solu¬ 
tion you introduce at one side, say a bit of glass, which has not been 
calcined, and of which the surface is consequently contaminated, i. e. 
beset with germinative particles. The vegetation takes its start from 
the surface of the glass. One after another Bacteria emerge into 
existence and visibility, and multiply with a rapidity which you can 
easily calculate on the datum that* each comes to perfection within 
about an hour after its birth. 
Having our bacterium, how does it manufacture its virus ? In order 
to obtain an answer to this question, I will ask your attention to the 
following experimental results, which, irrespectively of their bearing on 
the present question, are of value for the additional evidence they afford 
of the fundamental proposition of this lecture, viz. that septicoemia is not 
due to the direct action of living Bacteria on the blood and tissues. 
Some years ago Dr. Hiller, one of the most energetic and able of the 
opponents of the germ theory, made an experiment which has been the 
subject of much discussion. Having succeeded in collecting a consider¬ 
able mass of bacterial material, that is, of Bacteria obtained from various 
fluids in advanced putrefaction, on a filter, he washed the mass, just as one 
washes a precipitate a great number of times, and injected it in repeated 
doses into the circulating blood of animals. The injections were entirely 
without effect. Hiller next proceeded to inoculate himself with the 
same material, and again without effect. The advocates of Bacteria at 
once objected to Hiller’s experiment, that the Bacteria, not being accus¬ 
tomed to distilled water, were so injured by the repeated washings that 
they had lost their activity. The criticism, however, might j.ust as well 
have been spared ; for it afforded Hiller the opportunity of proving, by 
experiment, which was, of course, easy enough, that the washed Bacteria 
were as lively and as capable of development as ever. 
But there is another way in which inactive bacterial liquids can be 
prepared ; a way to which 1 have already adverted. In any cultivation 
of Bacteria in a nutrient solution, the first crop (if I may use the expres¬ 
sion) is always inert. It is not until the Bacteria have gone on for many 
days dividing and dividing that they begin to develop their poisonous 
properties, at all events in appreciable quantity. This can scarcely 
mean an thing else than that the mode of vegetation changes, viz. that the 
Bacteria first formed have their place taken by others, of which the form 
and the physiological endowments are different. Every one who is 
familiar with the growth of Bacteria in cultivating liquids, knows that 
there is a marked difference in appearance between the first and subse¬ 
quent growths, the former consisting mostly of rods (Bacteria proper) 
which appear early, the latter of spheroids or micrococci. They differ 
not only in form, but also in the fact that whereas the rods are endowed 
with great mobility and appear to act independently, as if each had a 
consciousness of its own; the latter are held together in masses by 
transparent interstitial substance (glasa) and usually form a scum or 
pellicle on the surface of the liquid. The meaning of these facts seems 
to be this. It is obvious that in every liquid in which successive gene¬ 
rations of organisms grow in the way I have described, each generation 
must alter the composition of the liquid; and that' this change may 
consist not merely in the discharge into the liquid from the bodies of 
such organisms of the “ waste products ” of their vital processes, but also 
