Page 104 - My FlipBook
P. 104
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they are exposed to the air, but they grow without air a) so.
(Passes tubes to class.)
Among those planted upon gelatin there is a little solu-
tion of the gelatin in each one. Some have no pus micro-
organisms, but have others that dissolve the gelatin very
sHghtly, and you will see that there is a little depression
each one of the colonies has sunk just a little in the media.
Some of the colonies have made but slight growth. They
are the caries fungi or Streptococcus media. Caries fungi
grow very slowly indeed upon gelatin—they require more
heat. Remember, this gelatin will melt down at a little over
80 degrees, and we cannot keep it in a higher temperature
safely. There are several of these tubes that were planted
a little earlier. This was planted on the i6th, and has one
lone colony of a micro-organism that is dissolving the gela-
tin slightly, Staphylococcus Salivaris, and a number of small
'colonies of caries fungus. You will remember I planted
three more tubes. In one of these I got the Staphylococcus
Pyogenes Albus. The first picture I had on the screen the
•other day, and No. i in the illustrations that will accompany
your lectures, was of this Staphylococcus. Of these there
are four varieties—the Albus, or white ; the Aureus, or yel-
low ; the Citreus, or citron color, and the fourth, that we find
in the mouth continually, is a white Staphylococcus, but
somewhat different from the Staphylococcus Pyogenes Al-
bus — probably the same coccus modified by its growth in the
mouth. It has all of the morphological characters of the
Staphylococcus Pyogenes Albus, but it liquefies gelatin but
sHghtly and its colonies seem to break up and become ragged
about the edges when they attain a Httle size, while the
colonies of the other remain smooth. This enables us to
differentiate between them easily. But this is not the modified
Staphylococcus ; it has all the characters of the Staphylococ-
cus Pyogenes Albus. It has liquefied this gelatin so that
most of it runs. I have replanted this twice since, and I
have here a tube that I planted on the i8th, and one planted
on the 19th, Saturday evening, just before I went home. In
both of these a part of the gelatin is Hquefied so that it will
run. You will notice that in the growth of this micro-or-
ganism the gelatin is liquefied as the growth reaches it, and
it will go on and on until it is all melted down. I have ob-
92
they are exposed to the air, but they grow without air a) so.
(Passes tubes to class.)
Among those planted upon gelatin there is a little solu-
tion of the gelatin in each one. Some have no pus micro-
organisms, but have others that dissolve the gelatin very
sHghtly, and you will see that there is a little depression
each one of the colonies has sunk just a little in the media.
Some of the colonies have made but slight growth. They
are the caries fungi or Streptococcus media. Caries fungi
grow very slowly indeed upon gelatin—they require more
heat. Remember, this gelatin will melt down at a little over
80 degrees, and we cannot keep it in a higher temperature
safely. There are several of these tubes that were planted
a little earlier. This was planted on the i6th, and has one
lone colony of a micro-organism that is dissolving the gela-
tin slightly, Staphylococcus Salivaris, and a number of small
'colonies of caries fungus. You will remember I planted
three more tubes. In one of these I got the Staphylococcus
Pyogenes Albus. The first picture I had on the screen the
•other day, and No. i in the illustrations that will accompany
your lectures, was of this Staphylococcus. Of these there
are four varieties—the Albus, or white ; the Aureus, or yel-
low ; the Citreus, or citron color, and the fourth, that we find
in the mouth continually, is a white Staphylococcus, but
somewhat different from the Staphylococcus Pyogenes Al-
bus — probably the same coccus modified by its growth in the
mouth. It has all of the morphological characters of the
Staphylococcus Pyogenes Albus, but it liquefies gelatin but
sHghtly and its colonies seem to break up and become ragged
about the edges when they attain a Httle size, while the
colonies of the other remain smooth. This enables us to
differentiate between them easily. But this is not the modified
Staphylococcus ; it has all the characters of the Staphylococ-
cus Pyogenes Albus. It has liquefied this gelatin so that
most of it runs. I have replanted this twice since, and I
have here a tube that I planted on the i8th, and one planted
on the 19th, Saturday evening, just before I went home. In
both of these a part of the gelatin is Hquefied so that it will
run. You will notice that in the growth of this micro-or-
ganism the gelatin is liquefied as the growth reaches it, and
it will go on and on until it is all melted down. I have ob-
92
