September 17,1870.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
237 
complex than the materials of the plant, but of great 
complexity; and, accordingly, the notion which Liebig- 
had that the yeast-cell is active in the proportion as its 
materials are undergoing- complete analyses or breakings 
up, and forming ammonia and carbonic acid, is not now 
entertained by that distinguished philosopher. 
Some time ago, an exceedingly important experiment 
was made by M. Pasteur, with a dew of testing the 
vital functions of the yeast-cells in a definite way. The 
statements which I have made to you contain a good 
many terms which are exceedingly general, as, for in¬ 
stance, the allusions to diastase. We really do not 
know what that is. Wo know about what sort of a 
thing it is made from, hut not definitely. And the same 
with tho nitrogenous products which are given off by 
the yeast-cells; we know something about them, but 
only a little. Pasteur put into a solution of sugar, in 
which some yeast-particles were present, some ammonia 
combined with an acid, and at the same time he put 
some of the ashes of other yeast-cells. He took a certain 
quantity of yeast and burnt it, so as to remove by oxida¬ 
tion the carbon, hydrogen and nitrogen of the substance, 
and the earth substances which remained, which are es¬ 
sential to the formation of a new yeast-cell, he put into 
some fermenting liquid, together with some salt of am¬ 
monia. When he did that, he really was treating the 
yeast-cells very much in the same way as a good farmer 
treats the wheat plant. If you want a wheat plant to 
increase rapidly, you must, in the first place, take care to 
supply to it all that the wheat plant takes up in the 
shape of mineral matter from the soil, and the best way 
to find that out is to burn some wheat, and see what is 
left. Then you must supply plenty of ammonia, and 
the more ammonia you supply up to a certain extent, 
the more rapidly does the wheat grow, by building 
up various simple substances into the complex sub¬ 
stance, gluten, which I was speaking of just now. 
Pasteur put into such a mixture a few little cells of the 
yeast, and they did not thrive. They did transform 
some sugar into alcohol and carbonic acid, but they evi¬ 
dently were not at home, and at the end of a certain 
time, I forget how long, he found there was actually 
a smaller weight of yeast present than he had put in. 
That was a very different result from what happens 
when nitrogen is supplied to the yeast-plant in the form 
which I mentioned just now as the usual one; and I 
think the fact is most instructive, and serves to show us 
what kind of a being the yeast-cell really is,—I mean 
whether it should be classed among animal or vegetable 
beings. I need hardly say that absolute distinctions 
amongst beings which we find in nature are out of the 
question ; we do not generally get any absolute line of 
demarcation, for one class flows over into the other; but 
still the ideas which serve us to classify organic and 
other beings are exceedingly important, and in a case 
like this it is certainly of considerable interest to have 
some leading idea, by which one may see whether there 
is a reason for placing these beings amongst vegetable or 
animal organisms, and we cannot help giving special 
weight in that respect to the kind of process which the 
respective classes of beings carry out in their organisms. 
Plants build up complex substances from simple. All 
the most complex substances that we can get are made 
in the organisms of plants. They may have been taken - 
over by animals from plants, but they are formed in the 
main by plants. And the chief chemical activity of ‘ 
animals is precisely opposite; they take those complex - 
substances, and break them down, by means of their . 
vital functions, to the simple products which are exhaled 
and given off in the processes of animal life. Therefore, ' 
the question whether the process which the yeast carries ; 
on is a synthetical process, a building up, or whether 
it is in the main an analytical process, is certainly one of ' 
the most important which can guide us. Now, I think 
what I have said must appear to you all most conclusive 
in that respect,—that what we know best regarding the 
nature of the yeast-cells, the food which we know they 
take in large quantities, and upon which they live, 
is certainly exceedingly complex, and what the yeast- 
cells take up in preference is certainly sugar, and the 
very complex nitrogenous substances which are present 
in solution in the malt, and tho products which they 
give off, are exceedingly simple in comparison. Their 
functions are in the main (those which wo know best, 
at any rate) analogous to those which take place in 
animal organisms, and are most remote from those which 
take place in vegetable organisms. 
In a paper which he has recently written on the subject 
of fermentation, Liebig- has drawn attention, amongst 
other things, to the circumstance that the common alco¬ 
holic ferment can be made to eat tartaric acid. If you 
were to neutralize a solution of some of these crystals 
in water, and put with the solution some yeast-cells, at 
the same time supplying some nitrogenous material, tho 
yeast-plants would grow, and transform that into other 
substances. In the same way, if you were to put in 
some of this malic acid (which got its name from the 
circumstance that it is present in sour apples), the yeast- 
cells would also transform that; and the same in other 
cases. One of the most remarkable decompositions is 
that of nitric acid, which, by tho action of the yeast- 
cells, is deprived of some of its oxygen, and converted 
into nitrous acid, so that it would appear that the plant 
can actually assimilate or eat the nitrates, forming these 
simpler derivatives from them. 
There is one case which I should like to show you, 
of an inorganic action, one in which there is no vital 
process concerned, but it bears a sort of general re¬ 
semblance to what I conceive to be the principle of 
those which I have been speaking of. I have here a 
piece of platinum in a peculiar state, which is well de¬ 
scribed by the term “ spongy.” If I hold it in the 
flame of common coal-gas mixed with air, from a Bunsen 
burner, the spongy platinum eats the air or the oxygen 
contained in it and the gas. The word “eat” is not 
really so inappropriate as it may seem. If I were to put 
this spongy platinum into oxygen, I should find that it 
would combine a quantity of oxygen into its substance, 
and make it part of itself, and the same with regard to 
the coal-gas. So that here you see, from the heat which 
was given off, the substance is really effecting a chemical 
change upon the materials which it absorbs, and it effects 
that change in its own substance. It is admitted that, 
in some way or other, the yeast organisms—I will not 
again call them plants—actually assimilate and make 
part of themselves the sugar, or tartaric acid, or what¬ 
ever it may be which they decompose; but they do not 
give off that substance which they have eaten in the 
same form. They give off its elements, after they have 
undergone a rearrangement in other ways. At our next 
meeting I propose to bring before you some different 
considerations regarding the vital functions of these or¬ 
ganisms, and some points which bear upon questions of 
sanitary importance. 
AMERICAN PHARMACEUTICAL ASSOCIATION. 
From a circular issued by the Permanent Secretary, 
Mr. John M. Maisch, we learn that the Eighteenth 
Annual Meeting of the American Pharmaceutical Asso¬ 
ciation was to be held on Tuesday the 13th of Septem¬ 
ber, in the building of the University of Maryland, in 
the city of Baltimore. Ample accommodation has been 
secured in the same building- for the exhibition of drugs, 
preparations, apparatus, models, and specimens interest¬ 
ing- to and connected with tho business of the pharma¬ 
cist. The central position of Baltimore, and the impor¬ 
tant subjects to be reported and acted upon, are expected 
to render this meeting a very interesting one. 
