ON THE LACTIC FERMENTATION 
AND ITS BEARINGS ON PATHOLOGY * 
[Transactions of the Pathological Society of London, vol. xxix, 1878.] 
A FEW years ago it would have seemed very improbable that the souring 
of milk should have any bearings upon human disease; but all will now be 
ready to admit that the study of fermentative changes deservedly occupies 
a prominent place in the minds of pathologists. 
In order that any sure steps may be taken to elucidate the real nature 
of the various important diseases which may be presumed to be of a fermenta- 
tive nature, such as the specific fevers or pyaemia, the first essential, as it appears 
to me, is that we should have clear ideas, based upon positive knowledge, with 
regard to the more simple forms of fermentation, if I may so speak—more simple 
because they can be conducted and investigated in our laboratories. 
It may be said, indeed, that such information has been already afforded 
us by the researches of Pasteur and others who have followed in his wake, tending 
to prove that all true fermentations of organic liquids are due to the develop- 
ment of organisms within them; and I confess that for my own part I am 
disposed to agree with that view. But this opinion is by no means universal 
in our profession. We meet with statements by men of very high position, 
both as physiologists and pathologists, to the effect that in various fermenta- 
tions—such, for example, as putrefaction—the bacteria which are found to be 
present may, for aught we know, be mere accidental concomitants, not causes, 
of the fermentative change. And such being the case, it seemed desirable to 
obtain, if possible, entirely conclusive evidence upon the subject. 
About four months ago I made an attempt of this kind with regard to the 
lactic fermentation ; and I propose on the present occasion to bring forward 
the results arrived at, and at the same time to afford the members of the Patho- 
logical Society an opportunity of seeing with their own eyes samples of the 
preparations which resulted from that inquiry, and on which my conclusions 
are based. 
First, however, I desire to describe my method of experimenting, which, 
1 This communication, made to the Society without manuscript, on the 18th of December, 1877, is 
here given in its original form. In preparing it for the press, however, matter has been introduced 
including some points into which the time at my disposal did not allow me to enter, and also some 
facts since ascertained, together with considerations arising from them. 
LISTER I Aa 
