AND OTHER FERMENTATIVE CHANGES 295 
But though disappointed of the results which I had hoped to have obtained 
from this oidium, I made some other observations upon it which proved to be of 
considerable interest. The remarkable conidial development which took place 
from it in water seemed such a striking instance of change of habit in the plant 
induced by a new medium, that I thought it worth while to try what effect 
would be produced upon it by various other liquids, and among the rest by 
unboiled and uncontaminated urine ; and on the 2i1st of August, 1872, I intro- 
duced into one of a series of ‘heated’ and covered glasses of that fluid, prepared on 
the roth of the month, and as yet unaltered, a minute portion of the organism 
from the glass of fresh Pasteur’s solution, where, as before mentioned, it was 
growing slowly in a filamentous condition; the delicate threads becoming 
broken up in the process, and diffused in an invisible form in the liquid. At 
the same time, for the sake of comparison, I inoculated from the same source 
another glass of Pasteur’s solution, as well as other lquids to which I need 
not here allude. In the fresh glass of Pasteur’s solution the growth proceeded, 
as in the previous one, in the form of branched and septate filaments, one of 
which is represented in outline at g, Plate VIII, on a smaller scale than the 
rest of the plate, while g’ gives in detail a portion of the same filament as seen 
under the usual higher power: and in the course of two days the naked eye 
detected white specks upon the side of the glass, which the pocket-lens showed as 
little woolly tufts. Meanwhile, in the urine the glass had also become sprinkled 
with white specks, but under the pocket-magnifier, while some of them were 
filamentous, as in the Pasteur’s solution, many presented a granular appearance. 
In examining the growth microscopically, I availed myself of an arrange- 
ment which I have often found advantageous. At the time of inoculation I had 
introduced into the urine a small plate of glass, with pieces of fine silver wire 
connected with its ends in the form of hooks, by which it could be suspended 
from the rim of the glass; so that, lying horizontally in the liquid, it might 
arrest as they fell organisms diffused through it. The little apparatus had of 
course been previously purified by heat. Such a plate being carefully removed 
with ‘heated’ forceps after development has advanced to any desired degree, 
and covered with a slip of thin glass, permits the examination of any growth 
that may have formed upon it, in a comparatively undisturbed condition. 
Thus, in the present instance, I was enabled to see im situ with the microscope 
the plants which the pocket magnifier had revealed. Under a low power they 
presented appearances such as are shown at a, b, and c, Plate IX, a being a 
purely filamentous growth, c a granular group, and 0 one exhibiting both char- 
acters in combination. Under the high power the granular parts were found to 
be composed either of groups of free pullulating cells of oval form, generally 
