WATER, WATER ANALYSIS, AND THE MICROSCOPE. 283. 
and the mode of its use conduces singularly enough to its constant 
action. When the plant is well-covered with liquor, it grows more, 
as indicated in the diagram, but when nearly all the ginger-beer 
has been baled out, the air has free access, and rejuvenescence is 
again effected. 
You will notice that the spores occur in masses, not unlike the 
description given, as boiled rice; this is owing to the matting to- 
gether of the mycelioid filaments, as you may see by working at it 
with the microscope. 
I say there is but little doubt that the Jk of this plant is com- 
posed of the Mucor ferment, but it is by no means wholly composed 
of it; there are many cells of ordinary sedimentary yeast to be 
found in the field, mixed also with filaments, due, no doubt, to 
Penicillium and Aspergillus, and there will be found others of a 
more minute description, such as we are apt to classify, when seen, 
under the general term bacteria. Two of the samples I will show 
you under the microscope have been stained with Bismarck brown 
in order to show these bacteria more plainly. To show you a yeast 
which appears spontaneously, and which is capable of exciting fer- 
mentation in sugar solutions, I have a slide of fungus from sugar- 
house liquor; it is one of the ferments produced by the sub-aqueous 
vegetation of some of the mould fungi; there are to be seen the 
long filaments and the cells increasing by budding just as in the 
ginger-beer plant. 
To sum up—the ginger-beer plant is a very impure yeast or 
leaven, of a different character to ordinary brewer’s yeast or Ger- 
man barm. It consists of many varieties of cells, oval, round, and 
some extremely elongated; the whole are bound together by my- 
celioid filaments which increase as the air has free acces to it. The 
smaller or bacteroid cell I have not had sufficient time to work out, 
but my impression is that they induce the peculiar flavour found in 
the liquid. Certain it is that by cultivation this can be consider- 
ably reduced in quantity, and the flavour then alters very materially. 
I have not had sufficient leisure to give the aerial form of this 
fungi, but this may form another communication to you at some 
future date. 
WATER, WATER ANALYSIS, AND THE 
MICROSCOPE. 
URING the prevalence of Cholera in Egypt, public attention 
was often called to our water supply ; every one was on the 
alert to discover something abnormal in drinking water, and it 
would have been strange indeed had nothing been observed in the 
