

OF PUTREFACTION AND OTHER FERMENTATIVE CHANGES. 341 
loose and imperfect character, like that represented at d, Plate XXV., 
while the chief product of the development was pairs of oval vacuoled 
corpuscles, resembling those of the scum of the urine at an early period. 
And the result was not only a granular deposit on the side of the glass, but 
aseum upon the surface, whereas neither of the other glasses of PasTEur’s 
solution had shown any scum. This difference between the glasses ‘continued 
as long as they were kept under observation ; that inoculated with the toruloid © 
scum still presenting a growth mainly of scum, without any filamentous appear- 
ance visible to the naked eye till the 14th of September, eighteen days after 
inoculation, while the other two glasses had still no scum whatever, and 
exhibited abundant conspicuous woolly tufts. This fact is of itself proof ofa 
very important general truth, viz., that a particular habit of growth impressed 
upon an organism by temporary residence in a new medium may sometimes be 
retained for a long period after it has been restored to its former habitat. The 
effect of the stale urme upon this plant was to substitute the corpuscular for 
the filamentous mode of development; and although, when returned to the 
PASTEUR’S solution, there was a degree of recovery, as indicated by the change 
from the spherical nucleated cells to the oval vacuoled corpuscles, and still 
more by the occasional appearance of coarse imperfect threads, yet the original 
character was not restored during the eighteen days of observation. And this 
circumstance is the more interesting, when it is remembered that the corpus- 
cular variety appeared to differ from the filamentous in fermentative power, the 
former being more energetic in its effect on urine than the latter. - Facts 
of this kind may tend to elucidate points of great importance in the history of 
contagious diseases, such as the greater virulence of such disorders at some 
periods than at others. For it seems highly probable from analogy that the 
materies morbi may be of the nature of minute organisms; and if this be the 
case, we can understand, from what we have seen of the plant under considera- 
tion, that differences of energy in the virus may be occasioned by varying cir- 
cumstances. 
The failure of the plant to resume the filamentous habit when returned.to 
PAsTEvR’s solution, makes it the more remarkable that it should have recovered 
that power in fresh urine, implying that this secretion, when in a perfectly 
unaltered condition, is a still more favourable medium for the organism, permit- 
ting a degree of recovery which was impossible in PastEur’s fluid. 
The last fact which I have to mention regarding this plant, is its behaviour 
in an albuminous liquid. This medium, which also proved valuable in experi- 
ments to be described in a later part of this paper, was prepared on the same 
principle as the unboiled urine, by taking the material uncontaminated from its 
natural receptacle, by aid of antiseptic measures. An egg, known to have been - 
VOL, XXVII. PART III. 4U 
