December 31, 1870.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
535 
on other bodies, as shown by an experiment made by 
Humboldt many years ago. He got some grains of 
wheat from Egyptian mummies, which had been so long 
n,t rest that they were not inclined to grow, in fact, they 
could not he got to grow in the ordinary way. How¬ 
ever, he stimulated them to activity by immersing them 
in a little chlorine "water. It is well known to chemists 
that chlorine in the presence of water does oxidize, or 
cause the oxygen to separate and pass over to common 
organic substances capable of combining with it. Hum¬ 
boldt actually stimulated these sleepy wheat grains to 
life, so that they grew and germinated, and their de¬ 
scendants are still in existence, by the mere action of 
oxygen developed in that way. 
In the processes of wine-making and wine-keeping, 
the presence of air is one of the most important matters 
which have to be considered, and there has prevailed, 
and I ought to say there still prevails, to a certain ex- 
.tent, a difference of opinion regarding the functions of 
oxygen in these pi'oeesses. On tlie one hand, it is known, 
as a matter of fact, that processes of fermentation are 
performed under conditions such as that air has access to 
the substance. No actual wine or beer-making has yet 
been pei'formed on a large scale on such conditions as to 
exclude oxygen. On the other hand, the experiments of 
Gay-Lussac established cleai'ly that it is necessary. In 
some cases, however-, in wine-making, it has been thought 
desirable to facilitate the access of air to the substance; 
while other wine-makers think, on the contrary, that in 
the first precess as little air should be present as pos¬ 
sible; but there has always been some. The juice fii-st 
•expressed from the grapes has been very carefully exa¬ 
mined with regard to the gases contained in it. If air 
has access to it, it is always necessary to know, in order 
to judge whether the air acts upon it, whether the air is 
dissolved by it, and whethei', if dissolved by it, it is still 
to be found in the grape-juice as such, or whether it has 
undergone combination. Now, every case of the exa¬ 
mination of must, or fresh grape-juice, wdiich is not fer¬ 
mented, has shown that it contains a considerable quantity 
of gas, but no case has been established of free oxygen 
being present in it. Carbonic acid gas is present in it in 
a. considerable quantity, and also nitrogen, in proof that 
air had had access to it, but the oxygen which was taken 
■up at the same time with the nitrogen from the air, was 
not to be got out from that must again. It had been 
taken up, and it had entered into combination with the 
substance, so that all the oxygen present was actually 
combined chemically with it. In that l’espect a good 
many observations have been made by various chemists, 
but I ought especially to quote those of M. Pasteur, I 
which are exceedingly careful and valuable. He has 
shown that this substance not only eats oxygen, but di¬ 
gests it. The oxygen is not to be found in it as such. 
It is only present in the form of a compound, which is 
formed by its action on the oi-ganic matters thei'e present. 
Then, when the wine-juice has been expressed, and when 
it has been allowed to remain some time in a suitable 
place, so as to undergo fermentation, with a considerable 
variety of treatment in different places with regard to 
ail-, for in some places it is thought desirable that the 
fermentation should be allowed to take place in open 
vessels, or in vessels to which the air can have access as 
freely as possible, whereas in other cases special care is 
taken to cover as completely as possible the vessels in 
which the feimentation is taking place, so that the air 
may have as little access as possible to the fermenting 
‘Substance,—and I believe it is impossible to give any one 
general rule with regard to the best process for all cases 
ot fermentation, because the matei-ials which are sub¬ 
jected to fermentation vary so considerably; they differ 
from one another in their composition so materially, and 
there are also other circumstances which are different,— 
for instance, the temperature, which has an important 
influence. Not only is the temperatui-e in some localities 
higher than in others, but other circumstances are also 
different, and it would not be right to say, because air is 
found to be perfectly useless in some well-established 
cases during fermentation, that for that reason, it ought 
to be excluded, or even that it may be excluded, in all 
other cases of apparently similar fermentation. As far 
as a general rule can bo laid down from present expe- 
l'icnce, I think it does appear certain that oxygen plays 
no part in the pi’oeess after the first expression of the 
juice. Once the fermentation has commenced, it appears 
to go on as well if air is excluded from the substance as 
if air has access to it. There is, however, one cii-cum- 
stance which is considered by persons of considerable 
experience to be important in this matter, and which I 
ought therefore to mention, viz., that when fermentation 
takes place at a low temperature—-and some fermenta¬ 
tions are, with great care, kept at a low tempei-ature— 
the products are found to be superior if the whole pi'oeess 
is carried on, the temperature being kept exceedingly 
low, and in those cases it appears that an open vessel is 
certainly not in any degree detrimental. It is cus¬ 
tomary, in fact, to use an open tub when the temperature 
is low; and, on the contrary, it is usual to use a partially 
closed vessel, of course allowing for the escape of car¬ 
bonic acid, when the temperature is comparatively high. 
When the fii-st vinous fermentation has completed itself, 
it is customary, in the wine-gi’owing countries, to put 
the still active liquid into casks, and the slower precess of 
fermentation then goes on, which lasts a considerable time. 
During this second fennentation, there is very much the 
same kind of condition present as in the first, and thei'e 
is always formed, in this subsequent fermentation, a con¬ 
siderable quantity of deposit, which is afterwards x-e- 
moved with much cax-e ; either the supernatant liquid is" 
carefully decanted, oi', in some cases, it is removed by a 
process of rough filtration. The subsequent treatment 
of the wine, I mean the keeping of it in casks or cellars, 
and the subsequent keeping in bottles—and these two 
processes of keeping it in casks and keeping it in bottles 
are quite distinct,—ai’e not usually considei'ed as 
forming part of the process of wine-making. It appears, 
however, from the investigations of M. Pasteur, that 
changes take place in the composition and the matci'ials 
by these processes, which really are as essential to the 
composition of the product as any other part of it, and 
that they ought to be considered as later parts of the 
process of wine-making. In fact, the process of wine¬ 
keeping is, in theory, not to be separated from the 
pi'oeess of wine-making, the keeping being a pi-ocess 
making it more perfect than it was when first turned 
out of the fei-menting vessels. Common expei'ience cor¬ 
roborates that in a very remarkable way. Everybody 
knows the difference there is between new and old wine, 
and the changes which take place when the wine is 
being kept constitute certainly one of the most important 
pai’ts of the general subject of wine-making. Wine, 
when its fermentation has been completed, is. found to 
absorb air with considerable rapidity and avidity, and 
when endeavours are made to get out from this wine 
again the air which has been dissolved in it, it is found 
that some kinds of wine allow it to go, or part with it 
again, whilst other wines do not; and in this respect, a 
distinctive test is found between the qualities of the 
wine; for by obseiwing this difference in the facility 
with which they give up the air which they have dis¬ 
solved, and by comparing that with the qualities of 
wines in each case, a remarkable generalization has been 
ari'ived at. In this matter I speak upon the authority 
of others, for I have not confirmed it by my own obser¬ 
vations. But all that I do know fully cori'oboratcs.it. 
The rule is this, that whereas low-class wines, which 
people will not pUy much for, give up again almost com¬ 
pletely the air, which they have dissolved, superior kinds 
of wine do not give it up again, they only give up the 
nitrogen, and hold the oxygen fast. The oxygen, which 
is dissolved in both cases, is hold firmly, or. is digested 
by the high-class wines; but it is not digested, but 
