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am the only person who has been able to get a pure growth
of that organism. It will not grow at all on agar agar or
on gelatin, and that is the reason why it is so difficult to get
pure growths. Pure growths can only be had by other
means, and means that are exceedingly difficult. For in^
stance, when I have found it fairly plentiful in a growth I
have broken it up with vigorous stirring with a platinum
needle and have flowed it a drop at a time over agar agar
that is cooled upon a slide, and have searched that with the
microscope and found a single filament of this species, lying
to itself; gotten up that single filament with a needle, and
conveyed it to a tube of broth and obtained a pure growth.
When we get a pure growth of it, particularly if the growth
is upon a still, calm night, it will grow up as great white
festoons in the tube, and, looking through it at the light, it
is a brilliant white, the broth remaining perfectly clear; a
little shake, and it all drops to the bottom. The growth
cannot be maintained for but two or three generations in
artificial culture. It is probably not in any degree patho-
genic.
(Changing slides. Fig. 7.) This is one of the very fa-
miliar forms to cultivators of micro-organisms and a good
picture of it. It is a coccus still, but the growth form is dif-
ferent. It does not divide as the streptococcus divides, but
divides in fours ; each individual cell divides into four cells,
always upon two poles on one plane, however, so as to form
sheets. For instance (pointing out), here these are shown
just about as they are completely subdivided ; here is one
that is just getting ready to subdivide, and here is one that
is divided more completely upon one pole than the other;
here is one that is in the process of division, in which, on the
one side, the division in this direction is not yet seen, but it
will come out. Now we will often find these in eights. Here
are eigrht together ; they have divided the second time before
they have quite completely divided at one point, and so on.
This shows the method of division very completely. This
is a micro-organism that we find habitually in the mouths
of children. We do not find it so often in the mouths of
adults. It is a mild pathogenic organism and is frequently
found in association with other micro-organisms in diseased
conditions. In pneumonia we will generally find it in the

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