October 1, 1870.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
277 
vinegar and a"bout 4 per cent, of alcohol, and I then 
touched the surface of the liquid, which was perfectly 
clear, with a glass rod which had been in contact with 
the vinegar-plant, and left some little particles floating- 
on the surface of the liquid. These little particles, in 
the course of a day or two, spread over the liquid, and 
when this vessel came from University College this 
morning it was covered with a perfectly uniform film, 
consisting of little cells different from each of the others 
to w r hich I have called your attention, and quite dis¬ 
tinguishable under the microscope. I should state that 
after the mixture w-as first made, and after the vinegar- 
cells were put into it and allowed to grow on it, I sup¬ 
plied them with some additional food twice. On one 
occasion I added a somewhat larger quantity of alcohol 
than was intended, and the effect was that the cells 
were most injuriously affected. They constituted a 
dense, smooth, wdiite film, and this seemed almost to 
disappear, and on examination under the microscope it 
was found that they had shrunk—in fact, they had been 
killed by a too strong dose of alcohol. This w-as then 
allowed to evaporate, and the vinegar-cells very soon 
again spread over the liquid. I will now commence in 
another dish a similar experiment. I have in this bottle 
a mixture of yeast-water and alcoh:l, with a few drops 
of acetic acid in it. I wall pour this into the glass dish, 
and then put on to the surface some of these little fer¬ 
ments which I have here, and I have no doubt that if 
we allow this mixture to stand w r e shall find by our next 
meeting that it w-ill be covered over w-ith a smooth film, 
consisting of vinegar-cells, w-hich will be transforming 
the alcohol into acetic acid. I may show you the 
strength of the acid in this last instance by putting into 
it a slip of blue test-paper, wdiich you see is immediately 
coloured a deep red. 
With regard to the process by which these cells are 
propagated some exceedingly interesting experiments 
have been made under the microscope. Professor 
Mitscherlich and various others,—Pasteur among them, 
—have put little alcohol cells under the microscope, 
putting them first into a liquid upon which they could 
feed, and they have noticed that the cells, or some of 
them, gradually swelled out at one side,—that a little 
wart, if I may use the expression, made its appearance 
on one side ; that this increased in size until it became 
as large as the original cell, and then it became de¬ 
tached. The propagation of the alcohol cells, the wine 
ferment, has been seen by several observers to take 
place by a process of budding. I wfill show you the 
growing cells, by throwing on the screen, by means of 
an oxy-hydrogen lantern, a photograph of the wine fer¬ 
ment, some of which will, I believe, show a little excre¬ 
scence at the side, and the general arrangement of the 
cells will be easily detected. This is a photograph from 
a plate of M. Pasteur’s, and conveys an exact represen¬ 
tation of the appearance which the alcohol cells ordina¬ 
rily present. I will now show r you the photograph of 
the acetic ferments, and the difference in the general 
appearance is very striking. When examined carefully 
it wall be found that these little vinegar cells are in 
couples, little masses about tw r ice as long as they are 
broad, and by degrees they become strangulated at the 
waist, and ultimately separate. With a considerable 
magnifying power, it has been found that the wane cells 
contain granulated particles, but exceedingly little is 
yet known of their structure. Certainly one of the most 
promising directions for investigation in the phenomena 
of life is presented by the study of these various little 
organisms, wrhich w r e have so completely under our 
control. 
With regard to the processes by which these cells are 
propagated, I have mentioned already, that when certain 
liquids, capable of undergoing decomposition, are ex¬ 
posed to the air, some little cells gradually make their 
appearance in w-hat was at first quite an unaccountable 
manner. It was long supposed, and on very good au¬ 
thority, that the oxygen of the air was the active agent 
in transforming a fermentable substance into these little 
cells; and Gay-Lussac, one of the ablest of French 
chemists, who died a short time ago, made some very 
careful experiments with a view to decide that point. 
They led him to the conclusion that oxygen was all that 
was needed in order to initiate the process of fermenta¬ 
tion in the juice of grapes, which by itself does not fer¬ 
ment. It is worth while to state, in general terms, the 
nature of these experiments. He put into a glass vessel, 
closed by mercury, a small quantity of grape juice, which 
was expressed under mercury, so that it did not come in 
contact with air on its w-ay into the glass jar intended to 
receive it. This was then kept closed for some time 
without change. He then introduced oxygen, sometimes, 
from the atmosphere—I am now giving you an account 
partly of what w-as done by Gay-Lussac, and partly what 
w-as done by others—and sometimes the oxygen was de¬ 
rived from potassic chlorate. Air w-as used which had 
been passed through red-hot tubes, so that any vital or¬ 
ganisms in it must have been destroyed before reaching 
the grape-juice; and it was found that, in these cases, 
the access of the air to the substance did induce the 
formation of yeast-cells, and did induce a process of alco¬ 
holic fermentation in the liquid by their grow-th. The 
conclusion, therefore, appeared to be established that 
oxygen was all that w-as needed for the process. Since 
that time, however, other experiments have been made, 
w-ith precautions which were not observed by Gay- 
Lussac ; and I must especially quote a truly masterly 
investigator, Pasteur, whose extraordinary researches in 
this subject have certainly constituted an important era 
in our knowledge of it. Pasteur has made a great num¬ 
ber of experiments, partly such as those which had been 
made before, and partly fresh ones, of w-hich I will de¬ 
scribe a few characteristic samples. For instance, he- 
took little glass bulbs, w-ith a long neck bent in several 
places, like the one I hold in my hand. This little bulb 
contains some yeast-w r ater, and also about 10 per cent, of 
sugar, a mixture which is peculiarly susceptible of un¬ 
dergoing fermentation and decompositions of various 
kinds. When this w-as introduced into such a bulb, 
Pasteur boiled the liquid for some time, so that any 
little living particles w-hich might have entered the bulb 
with the liquid, by being exposed to the temperature of 
boiling water, might be killed, and also that any parti¬ 
cles which might be lodged in the neck of the flask w-ould 
be similarly treated and killed. Some of these bulbs he 
closed, sealing up the tubes whilst still full of steam, and 
he then put them by in a warm chamber, similar to that 
w-hich I just now alluded to as being of the temperature 
of 30° Centigrade, so that they should be under the con¬ 
ditions most favourable to the development of any little 
living organisms, if such could develope themselves. He 
so kept them for days, w-eeks, and months, and I am not 
sure that he did not keep some for years, and at the end 
of the w-hole time he found that in no case w-as there the 
production of these vital organisms. I told you that 
when the tube was closed the vessel w-as full of steam ; 
of course that steam was condensed on cooling, and left 
a partial vacuum above the liquid, and w-hen Pasteur 
opened the tube by breaking off the point, the air rushed 
in violently to fill the vacant space. He found that in 
almost every case, although not in all, after this air had 
rushed in, a process of decomposition commenced, and in 
some cases he found little animalcules, and various kinds- 
of mould in others, and he has described a considerable 
number of different organisms which he got in different 
bulbs in that manner. It so happened, also, that in one 
case the tube, I think accidentally, at first remained, un¬ 
sealed, that it was not kept from contact w-ith the air as 
the others were; still, to his amazement, Pasteur found 
that even in this one w-hich remained open there werc.no 
organisms, that it remained as unchanged as those w-hich 
were sealed up. Finding this, he repeated the experi¬ 
ment many times, making a great number of bulbs similar 
