
OF PUTREFACTION AND OTHER FERMENTATIVE CHANGES. 335 
with mere vacuoles and inconspicuous granules, and either free or in pairs, were 
now of spherical form destitute of vacuoles, but strongly nucleated, as shown at 
1, Plate XXV., and disposed in considerable irregular groups, as seen in the 
outline portions of the sketch. The same character was maintained by the scum 
in this glass during the rest of the time (fifteen days) that it was kept under 
observation, m being a sketch of its appearance after the lapse of ten days; so 
that the organism had assumed completely the appearance of a spherical torula. 
But it may be asked, Was I not deceived in supposing that the new toruloid 
form in the second inoculated glass had anything to do with the oidium? May 
it not have been a totally different species accidently present, just as the oidium 
itself was apparently adventitious in the yeast-glass? That all the oval cells 
should have disappeared within twenty-four hours, and given place to another 
species producing a scum of the same remarkable naked-eye appearance, seemed 
indeed very improbable; but, on the other hand, the difference of character in 
the cells was so remarkable, that if it was really only due to a modification of 
the same organism, it was desirable, if possible, to place the fact beyond doubt. 
With this object, on the 30th August, I mingled a morsel of the scum, by means 
of a “heated” glass rod, with a drop of Pastrur’s solution* on a “heated” 
slip of glass, and placed upon it a ‘‘ heated” piece of thin covering glass, and 
over this a larger plate of thin glass also “ heated,” overlapping the former one 
well on all sides, and luted down the margins of the upper glass with melted 
paraffin, applied with a hot steel pen. The object of this arrangement was 
that, while evaporation should be prevented by the paraffin luting, the interval 
between the thin glass plates might contain a supply of air to permit the growth 
of the fungus. I then selected for observation a group of the spherical cells 
near the edge of the liquid, and therefore near the air between the plates, and 
sketched them with camera lucida, as shown at n,, Plate XXV. This was at 
5.50 p.m. At 6.8 p.m., I noticed a change in the nuclei of the cells, such as I 
_ have often observed in spores preliminary to germination, as indicated at n,, 
and by 11 p.m., the object being still undisturbed under the microscope, the 
lowest of the cells had not only increased in size, but had produced a consider- 
able elongated sprout (see ,), while the other cells were all markedly changed 
in the character of their nuclei. At midnight the sprout from the lowest cell 
had itself produced another sprout, also of oval form (see n,), and by 7.45 
hext morning, when I next looked at the cbject, two other cells had been 
produced from the last sprout, while some, if not all the other cells of the group, 
had also germinated, giving rise to the appearance shown at ,. And it will 
_ be observed that the products of this growth of the cells of the scum were not 
spherical and nucleated like them, but had the oval and vacuoled character of 
* The Pasrsur’s solution contained 1 per cent. of alcohol, for reasons with which I need not 
trouble the reader. 
