236 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. [September 17, 1870. 
BRITISH ASSOCIATION FOR THE ADVANCE¬ 
MENT OF SCIENCE. 
Meeting at Liverpool. 
The Fortieth Animal Meeting of the British Associa¬ 
tion commenced on Wednesday. It is the third visit 
the Association has made to Liverpool, and promises to 
be very successful. The first general meeting was held in 
the Philharmonic Hall. The retiring President, Pro¬ 
fessor Stokes, having vacated the chair, Professor Huxley, 
the President for the year, proceeded to deliver the 
customary address, the subject chosen by him being 
Spontaneous Generation. 
The business of the several sections commenced on 
Thursday morning. Among the events of interest an¬ 
nounced to take place during the meeting may be men¬ 
tioned the discourse of Professor Tyndall, on Friday, upon 
the Scientific Uses of the Imagination ; and the Lecture 
of Sir John Lubbock to working men, on Saturday, upon 
“ Savages.” The Mayor of Liverpool gives two soirees 
during the week. A soiree will also be given by Mr. 
Bickeysteth, for which one thousand invitations have 
been issued. The excursions, seven in number, are fixed 
to take place after the close of the business of the Asso¬ 
ciation. 
SHEFFIELD SCHOOL OF MEDICINE. 
The winter session of the Sheffield School of Medicine 
will commence on October 1st, when the Introductory 
Address will be delivered by the Rev. J. Lettis Short, 
and the Prizes distributed in the Anatomical Theatre at 
4 P.M. 
SOCIETY OF ARTS. 
On Fermentation. 
BY PROEESSOR A. W. WILLIAMSON, F.R.S. 
Lecture II. — continued. 
There is one other remarkable instance which I must 
give you, to show the difficulty in some cases of 
analysing these phenomena. It is the case of the metal 
platinum, which I can hardly describe better in general 
terms, as regards its properties, than by comparing it to 
gold. It is what is termed a noble metal; it does not 
dissolve in any ordinary acid; you might boil platinum 
in nitric acid for any length of time and it would not 
dissolve. On the other hand, silver is a metal which 
dissolves readily in this acid, and if you melt silver and 
put platinum into it, it will also melt, and you obtain a 
compound of the two metals mixed pretty uniformlv 
together. It was noticed that when such a button of 
platinum and silver is put into nitric acid, not only does 
the silver itself dissolve, as you would expect, but some 
of the platinum also dissolves with it; not the whole, 
but a portion. That seems, at first sight, favourable to 
the theory of contagion; it seems natural to suppose 
that the silver in dissolving has communicated the same 
tendency to the platinum, and made some of it dissolve. 
But that explanation will not do, and for this reason. 
When platinum is combined with anything else, I care 
not what, its properties are not the same as when un- 
combmed. The very essence of chemical combination 
18 jfu 7U P ar ^ GS which are in intimate contact unite, 
and that the compound possesses different properties from 
the original elements. We know that metals combine 
with one another; there are many cases known to us of 
the foicible union of metals, and we have no right to 
suppose in any case, unless we have actual proof of it 
that a metal is present in such a compound with its ordi- 
naiy properties, t herefore, it is not free platinum, but 
a compound of platinum and silver which dissolves and 
there are some compounds of platinum which dissolve in 
water, and others which dissolve in nitric acid, so that 
this process has really nothing to do with contagious 
action. 
In the composition of alcoholic ferments there are 
several substances of which we know very little at 
present, I am sorry to say, but the want of this know¬ 
ledge is so great that I have no doubt it will be soon 
supplied; certainly, this is a most important field for 
the investigation of naturalists who possess an accurate 
knowledge of chemical manipulation. I mean the simplest 
and lowest organisms, whose fimctions are of such im¬ 
portance in these changes, and certainly claim much care¬ 
ful investigation. But some of the things which we do 
know about the yeast-cells, I must now state, with rela¬ 
tion to the facts and ideas which we have just had before 
us. In the first place, with regard to their growth. It is 
very common, in the process of brewing, to feed the yeast- 
cells with a substance which is formed in the germination 
of barley. When barley is left in a moist state, at a suit¬ 
able temperature, it begins to sprout, and during that pro¬ 
cess there is a change in two of its constituents, which I 
showed you the other day. One is gluten, a body con¬ 
taining nitrogen, which I compared, for the sake of con¬ 
venience, to muscular fibre, being in reality very closely 
allied thereto in chemical composition, and during the 
germination of the seed this substance passes over into 
some product or products—I had better speak quite ge¬ 
nerally—known by the name of diastase. In the yeast- 
cells there is a substance very nearly resembling in 
composition this gluten, and it cannot be doubted that 
this gluten, or albuminous body as it is frequently called, 
is capable of undergoing a similar transformation into 
diastase, and of all foods the yeast-cell enjoys most 
those which contain diastase. I have a good many 
yeast-cells growing in a suitably heated chamber, and 
those which seem to thrive most are some which were 
put into an infusion of malt to which sugar was added. 
It is common, in the process of fermentation, to put in 
yeast in tolerable quantity, but the extent to which it 
grows depends upon the time for which it is left in 
contact in the material. I am told that the common 
proportion is about one-twentieth of the quantity of 
yeast required. For instance, if 20 lbs. of yeast are 
wanted to effect a given fermentation, you put into the 
liquid which has been fermented 1 lb. of yeast calculated 
in the dry state, and give it this diastase to feed upon. 
At the same time, there is sugar present in the liquid, 
and during the process of fermentation this pound weight 
of yeast increases more and more, by a process of true 
germination and growth. Professor Mitscherlich actually 
saw, under the microscope, some little cells of yeast 
sprout and put out, from the side of the parent cell, 
small cells, which gradually increased in size. The 
actual process, however, has not been seen by many 
observers. And not only does the yeast-cell in that way 
feed upon these albuminous bodies, which are grouped 
together by the name of diastase, but it also takes part 
of the sugar; and these are the two prominent facts 
which we know with regard to its food—that it feeds 
upon substances of those two classes; sugar, which con¬ 
tains no nitrogen, and also nitrogenous substances, which 
are formed by the partial breaking up of the gluten. 
On the other hand, its decomposition—I mean during 
its life ; I am not speaking of any decomposition which its 
materials may undergo if it is killed—gives off alcohol, 
carbonic acid, succinic acid and glycerine; in fact, the 
four chief products of ordinary alcoholic fermentation, 
which I enumerated to you the other day. And while 
these products are being given off, there is at the same 
time a considerable quantity of nitrogenous substances 
being given off. The albuminous matter in the yeast- 
cells is undergoing decomposition, and is giving off 
nitrogenous substances. There is not any well-authen¬ 
ticated case of the yeast-cell forming, during its active 
functions, products of complete breaking up or putre¬ 
factive decomposition ; all the products which we know 
best are substances of considerable complexity—less 
