PLATE (IV. 
From “ Pasteur’s Studies on Fermentation.’’ Macmillan & Co., London, 1879. 
“The engraving represents the different diseased ferments, together 
with some cells of alcoholic yeast, to show the relative size of these 
organisms.” 
Fig. 1 represents the ferments of turned beer, as it is called. These 
are filaments, simple or articulated into chains of different size, and having 
a diameter of about the thousandth part of a millimetre (about Ueo00 
inch). Under a very high power they are seen to be composed of many 
series of shorter filaments, immovable in their articulations, which are 
scarcely visible. 
In No. 2 are given the lactic ferments of wort and beer. These are 
small, fine, and contracted in their middle. They are generally detached, 
but sometimes occur in chains of two or three. Their diameter is a little 
greater than that of No. 1. 
In No. 3 are given the ferments of putrid wort or beer. These are 
mobile filaments, whose movements are more or less rapid, according to 
the temperature. Their diameter varies, but is for the most part greater 
than that of the filaments of Nos. 1 and 2. They generally appear at the 
commencement of fermentation, when it is slow, and are almost invari- 
ably the results of very defective working. 
In No. 4 are given the ferments of viscous wort, and those of ropy 
beer, which the French call filante. They form chaplets of nearly spher- 
ical grains. These ferments rarely occur in wort, still less frequently in 
beer. 
No. 5 represents the ferments of pungent, sour beer, which possesses an 
acetic odor. These ferments ogcur in the shape of chaplets, and consist 
of the mycoderma aceti, which bears a close resemblance to lactic ferments 
(No. 2), especially in the early stages of development. Their physiolog- 
ical functions are widely different, in spite of this similarity. 
The ferments given in No. 7 characterize beer of a peculiar acidity, 
which reminds one more or less of unripe, acid fruit, with an odor sui generis. 
These ferments occur in the form of grains which resemble little spheri- 
cal points, placed two together or forming squares. ‘They are generally 
found with the filaments of No. 1, and are more to be feared than the 
latter, which cause no very great deterioration in the quality of beer, 
when alone. When No. 7 is present, by itself or with No. 1, the beer ac- 
quires a sour taste and smell that render it detestable. We have met 
with this ferment existing in beer unaccompanied by other ferments, and 
have been convinced of its fatal effects. 
No. 6 represents one of the deposits belonging to wort. This must 
not be confounded with the deposits of diseased ferments. The latter 
are always visibly organized, whilst the former is shapeless, although it 
would not always be easy to decide between the two characters, if sev- 
eral samples of both descriptions were not present. This shapeless de- 
posit interferes with wort during its cooling. It is generally absent 
from beer, because it remains in the backs or on the coolers, or it may 
get entangled in the yeast during fermentation, and disappear with 
it. Among the shapeless granules of No. 6 may be discerned little 
spheres of different sizes and perfect regularity. These are balls of 
resinous and coloring matter that are frequently found in old beer at the 
bottom of bottles and casks. They resemble organized products, but 
are nothing of the kind. 
