18 
Hogg, on Vegetable Parasites. 
I divided into three equal portions, and, for the sake of con- 
venience, numbered 1, 2, and 3. Into Nos. 1 and 2 I put a 
few favus crusts ; No. 1 was put carefully away in a darkened 
place, the temperature of which was about 70° Fahr.; Nos. 2 
and 3 (the latter being simple sweetwort only) I exposed to 
a good light in my sitting-room window, where the tempera- 
ture ranges from 65° to 75° Fahr.; and each bottle was closely 
corked. On the second day, upon examining a portion of 
1 and 2 with a J -inch power, I found fermentation had com- 
menced, a film spreading over the whole surface of the liquid. 
In No. 1 were seen a fair quantity of yeast-cells, varying in form 
and size ; shown in PI. Ill, fig. 1, a. No. 2 was in a more ad- 
vanced stage, and some of the spores were rather larger than 
in No. 1. On the 4th and 5th days I took portions from all 
three bottles. That from No. 1 gave the best results ; the 
spores, yeast-cells, were more numerous and spherical in 
form, well filled with granular matter and numerous monili- 
form chains of smaller spores and amorphous stroma, shown 
in fig. 1, b. Compared with a small portion of fresh yeast 
from a beer-barrel, fig. 3, the cells and spores appeared 
about half the size (in the drawing, however, they are repre- 
sented too small). In specimen No. 2 spherical cells were 
fewer and smaller, with groups of ovoid spores mixed with 
torulse, and bacterium-like bodies floating rapidly about; 
here and there were seen tufts of penicillium, represented in 
fig. 2, a. In the sweet wort No. 3 were numerous ovoid 
spores, without granular matter, but highly refractive, and 
not unlike fat-globules. 
On the 10th day the changes seen in specimens taken from 
each bottle were still more marked. From No. 1 the spores 
were more numerous, but certainly rather smaller, and vari- 
able in form, and the greater portion of them were filled with 
granular or nuclear matter ; there were also groups of torulse 
mixed with still smaller spores, fig. 1, c. This specimen 
when the cork was removed from the bottle, gave indica- 
tions of the presence of carbonic acid, and the odour was 
that of good fresh beer, and the greater portion of the heavy 
yeast had fallen to the bottom of the bottle. No. 2, on the 
contrary, had become quite of a dark colour, smelt sour, and 
the spores had much decreased in size, granular matter with 
bacteria being by far the more numerous ; represented in 
fig. 2, b. The wort in No. 3 was still sweet^ — of a some- 
what vinous sweetness — and the top was thickly covered over 
by a whitish, flocculent, filamentous-looking mass of mould. 
A fortnight or rather more elapsed, and then another exa- 
mination gave somewhat similar results. No. 1 was still per- 
