888 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[May 6,1871. 
another, such as the unfolding of alcohol into other and 
water by contact with sulphuric acid; for although the 
acid causes such a wonderful change, it is not destroyed 
by the operation, and consequently, when once the pro¬ 
cess is set going an unlimited quantity of alcohol may 
be converted by the original acid. 
All the ferments are highly complex azotized sub¬ 
stances allied to albumen ; but while they possess this 
character in common, they may be divided into two 
groups—the one being living organisms, as yeast, and 
the other substances derived from various organic sources, 
such as albumen, gluten, casein, diastase, emulsin and a 
variety of others, all of which decay most rapidly when 
in a moist state. 
The authors of the ‘ Microscopical Dictionary ’ would 
“ exclude these substances from the ferments, and desire 
that the term fermentation be restricted to those changes 
which take place only through the agency of living or¬ 
ganisms or fungi;” regarding which they also say, “A 
general law appears to prevail throughout the fungi 
that their nutrition differs from that of all other plants 
in depending exclusively on the absorption and decom¬ 
position (with the evolution of carbonic acid gas) of 
organic compounds, therefore consisting of the perform¬ 
ance of the operation of fermentation on the organic 
matters on which they feed.” Rut as tlio chemical 
operations of the ferments are so similar, notwithstanding 
the wide difference in their organization, I consider there 
would be no advantage in separating them as proposed, 
as they form a distinct class of chemical phenomena. I 
have also to observe that it is not true that carbonic 
acid gas is always given off during fermentation, nor is 
it proved that it is evolved during the growth of all the 
fungi. The ferments to which I desire to call your 
attention are—• 
My coderma vini, or yeast, which converts sugar into 
alcohol. 
Boiled yeast, which converts sugar into gum and 
mannite—this transformation being called the vis¬ 
cous fermentation. 
Casein, which converts sugar into lactic acid and 
butyric acid ; this last conversion, however, being- 
attributed to the action of the vibrio and diastase, 
which converts starch into sugar. 
I shall have a few words to say on II. aceti, or the 
vinegar plant as some call it, which, although included 
by many among the ferments, is not so considered by 
chemists, for reasons I will hereafter explain. 
When a saccharine solution is left in contact with 
casein either in the form of fresh curd or cheese, the 
sugar is slowly transformed into lactic acid according to 
the following equation :—- 
Cane sugar, C 12 H n O n + HO = 2C G H G O c lactic acid. 
In this fermentation water is assimilated, but no gas is 
evolved. 
A solution of lactic acid, similarly treated, is trans¬ 
formed into butyric acid thus :— 
Lactic acid, 2C 6 H G 0 6 = C s H s 0 4 -f 4C0 2 + 4H. 
butyric Carbonic Hydrogen. 
Acid. Acid. 
In this fermentation both carbonic acid and hydrogen 
gases are evolved. It is a question not yet answered, 
whether these chemical changes are induced by mere 
contact with the decomposing- casein which is regarded 
as the ferment, or whether the minute organisms de¬ 
veloped in these solutions are the real ferments living- 
on the matters therein. One thing is certain, that in 
both fermentations living organisms abound, and they 
cannot grow without chemical changes taking place. 
“ M. Pasteur considers that a specific ferment is con¬ 
cerned in the production of the lactic acid fermentation, 
which spreads itself out as a grey substance over the 
surface of the sediment; and he asserts that this organ¬ 
ism, when once obtained, and a small quantity added to 
a solution of sugar, very rapidly converts it into lactic 
acid, provided the solution contain a small quantity of 
some nitrogenous substance. When this grey matter is 
examined by the microscope it is seen to consist of very 
small globules or very short articulations, either isolated 
or in threads, much smaller than yeast, and to exhibit 
very rapid gyratory motion.” 
I have not succeeded in obtaining this grey matter, 
but as the lactic acid fermentation goes on very slowly, 
and as this season of the year is not favourable for ex¬ 
periments on fermentation, it may not have had time to 
make its appearance. 
In order to observe the organisms which accompany 
the transformations of sugar, I watched the progress of 
the lactic acid fermentation of cane sugar, that of milk 
sugar by the gradual decomposition of milk, and also the 
viscous fermentation of cane sugar; for although I have 
seen no notice of any living organism being concerned 
in this fermentation, I thought it likely that the viscid 
ropy matter which is formed therein was probably due 
to some organic growth. 
Now in all these experiments I found that as soon as 
decomposition commenced, or at least was appreciable, 
but not until then, organic life was found in all the 
fluids; that in all cases they appeared on the surface 
before they wore seen in the body of the fluid, and 
that when first discovered they were not in an active 
condition, but as the decomposition progressed they 
became so, and moved through the fluid with rapidity, 
but those at the surface continued to be the most active. 
Those bodies are species of Vibrio and Bacterium. 
The milk used in the experiments was obtained per¬ 
fectly fresh and divided into three portions—one con¬ 
taining the cream after the milk had stood twenty-four 
hours, the second was simply the skimmed milk, while 
the third portion was some of the same, with the addition 
of chalk to neutralize the lactic acid as it was formed. 
During four days the milk remained sweet, and I de¬ 
tected no organism in any part of it; but at the end of 
the fourth day the cream had a sour odour, indicating 
that lactic acid had been formed, and a small speck 
taken from the surface with a needle exhibited a mass 
of Bacterium-like bodies which, when some distilled 
water was passed between the glass slide and cover, 
swarmed through the fluid with rapid and various 
capers.* On the fifth day the milk had become sour, 
and exhibited the same active organs, but in the portion 
to which the chalk was added they were neither so 
numerous nor so active. On the eighth day fungus 
spores and mycelia appeared on the surface of the 
cream, and the same was noticed, but in a lesser degree, 
some days afterwards on the two portions of milk; but 
as a considerable amount of lactic acid was formed before 
these objects made their appearance, I do not imagine 
they were concerned in the fermentation which was 
going on. 
But it was in the mixture of boiled yeast and sugar 
solution to produce the viscous fermentation that I 
found these bodies developed most rapidly, for in twenty- 
four hours after the mixture was made the fluid was 
covered with a thin film, which proved to be entirely 
these organisms packed closely together, so that no 
motion could be seen until some distilled water was 
added, when their activity was fully displayed. In the 
course of a few days the film had become a thick viscid 
scum, consisting entirely of these minute bodies, without 
a sign of any fungoid growth. 
From the fact that tlrese organisms grow most rapidly, 
and are in the greatest activity at the surface, it appears 
that air is necessary to produce these results, for in the 
mixture of milk and chalk from which carbonic acid was 
given off as the lactate of lime was formed, they were 
always in smaller quantity and less active condition: 
this vessel, too, was covered with a plate of glass, while 
all the other solutions were covered with paper. 
(To be continued.) 
* The motion here referred to is not due to the currents 
produced by capillary attraction, evaporation, etc. 
