Page 175 - My FlipBook

dantly and in the other none whatever would be formed.
Often when I have wished to get good stainings of these or-
ganisms they have formed such gelatinous masses that I have
found it exceedingly difificult to spread them upon a cover
glass, and again, when I have wished to exhibit the gelatinous
masses, I have had trouble to get them to form gelatine.
In a broth in which the organisms grow abundantly, with-
out the formation of gelatine, often the addition of a drop of
Eucalyptol will cause very abundant formation of gelatine. A
slight addition of carboHc acid, oil of cloves, or of several
other agents, in amounts insufficient to interfere with the
growth, will often do the same. In these cases the growth is
not in involution forms, as sometimes noted, but in the ordi-
nary form, and as abundant as when no gelatine has been
formed. Of course, the addition of too much of any of the
above agents will limit the growth. This so-called gelatine
is practically insoluble in any menstruum that I have been
able to find. I have tried alcohol, ether, various oils, acids
and the alkalies, to no purpose. It resists all of them. When
formed upon the sides of the glass vessel, it adheres with a
fair degree of firmness, but w4ien formed free in the fluid it
does not adhere to the glass on coming in contact with it.
If an actively progressive carious area be selected, that
has a fairly thick stratum of softened material, and the surface
be well washed with sterilized water, and the superficial por-
tions carefully trimmed away, repeating the washings until
only the innermost portions remain, and a bit of this be taken
up with a sterile instrument and conveyed to a tube of broth, a
pure growth of this fungus will generally be obtained. If a
bit of this material be planted upon Agar Agar, it will within
two or three days be fringed about with a pale, yellowish
growth, from which pure cultures may be transplanted. In
my experimental work the most frequent contaminations met
with in this kind of planting has been a white staphylococcus,
very similar to the staphylococcus pyogenes albus, but cer-
tainly much less liable to cause pus formation when intro-
duced into infiamed areas. It is probably the staphylococcus
pyogenes albus modified by continuous growth in the saliva.
It liquefies gelatine promptly, but less rapidly, than the
staphylococcus albus as we usually find it in abscesses. This
difference is very marked and serves to distinguish the one

163