366 ON THE LACTIC FERMENTATION 
days at the spot of inoculation, and gradually spread over the surface, and on 
examining with the microscope a portion taken with a purified needle from 
the vermilion spot, I found it teeming with bacteria, while a portion of 
the uncoloured cream in the vicinity showed nothing but the usual milk 
globules. Here then was a remarkable change going on in the milk fart 
passu with the development of bacteria, and doubtless occasioned by them, 
vet the bacteria themselves were of ordinary double-rod form and of about 
medium size... But various as were the changes produced in the milk by 
inoculation with water, there was no instance in the course of several such 
experiments of the lactic fermentation resulting from it. We see, therefore, 
from the facts which I have adduced, that the souring of milk, instead of being— 
as might naturally be supposed a priovt from seeing it occur constantly in all 
milk brought from a dairy—an inherent property of the liquid, is a change 
which, whether in boiled milk or unboiled, requires the introduction of something 
from without, and that something a scarce article, both in air and in water, 
except in dairies. Indeed, even in a dairy, though it exists in all the milk in 
the pans, it does not necessarily follow that it is the most frequent ferment in 
the air. I once took a glass of pure boiled milk to a dairy, and putting it down 
near one of the pans, removed its glass shade and glass cap, and left it exposed 
for a quarter of an hour, thinking it probable that the lactic fermentation would 
result. But it so happened that this was not the case. As a consequence of 
this exposure a filamentous fungus made its appearance in the milk, and also 
a bacterium, but a bacterium associated with a most extraordinary alteration, 
viz. viscidity in an extreme degree, reminding me of that of the glutinous drops 
that bead the spider’s web. On introducing a needle into the top of the liquid, 
and raising it, I drew out a barely visible thread, which was a yard and two 
inches long before it broke. Such was the special fermentation that resulted 
from exposure to the air on that occasion even in a dairy ; it so happened that, 
if any particles of the lactic ferment were floating in the air at all, none fell into 
the glass. 
This particular fermentation, therefore, from the conspicuousness of its 
effects and the rarity of the ferment under ordinary circumstances, seemed 
a peculiarly favourable one for investigation. 
And now, before proceeding further, I desire to correct a mistake into 
which I fell when investigating this same fermentation some years ago; for, 
next to the promulgation of new truth, the best thing, I conceive, that a man 
can do, is the recantation of published error. In the year 1873, I gave, in the 
* These experiments were performed in the early part of the year 1875, and were briefly alluded to 
in a paper in the Lancet of that year (see Lancet, April 3, 1875, p.470). Reprinted in vol. ii, p. 226. 
