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There is little reason to doubt that it is the same set of activities which renders the animal immune. The forces which drive off the invading bacteria in one case are still present to prevent a second attack of the same species of bacterium.
The fluid is lashed rhythmically by these fibers, and a spiral movement of the utmost grace results. Then do the intermediate forms that move also possess these flagella, and does this least form in nature, viz., Bacterium termo, accomplish its bounding and rebounding movements in the same way?
To cite only those whose origin is well known, we may mention the bacterium that causes charbon, the micrococcus of chicken cholera, and that of hog measles. It will be seen from this sketch how important the study of these organisms is to man, since be must defend his body against their invasions or utilize them for bringing about useful chemical modifications in organic matters. Our Servants.
I have stated that they were the inevitable accompaniments of putrescence and decay. You learned from a previous illustration the general appearance of the Bacteria; they are the earliest to appear whenever putrefaction shows itself. In fact the pioneer is this the ubiquitous Bacterium termo. The order of succession of the other forms is by no means certain.
If we had found a wriggle, or a zigzag, or a shoot from one side to the other, in this last flask, what a scare there would have been, to be sure, in the schools of the prophets! Talk about your megatherium and your megalosaurus, what are these to the bacterium and the vibrio? These are the dreadful monsters of today.
The difficulty of giving such a list is rendered greater from the fact that we have in recent years learned that the same species of pathogenic bacterium may produce different results under different conditions.
In its most general sense, the term microbe designates certain colorless algæ belonging to the family Bacteriaceæ, the principal forms of which are known under the name of Micrococcus. Bacterium, Bacillus. Vibrio, /Spirillum, etc.
If a definite species of bacterium causes a disease and we can cultivate the organism in the laboratory, it is easy to find some drugs which will be fatal to its growth, and these same drugs, it would seem, should be valuable as medicines in these diseases. This hope has, however, proved largely illusive.
At the lowest temperature at which this parasite can be cultivated that is to say, about +16 degrees Centigrade the bacterium does not produce germs at any rate, for a very long time. The shapes of the minute microbe at this lowest limit of its development are irregular, in the form of balls and pears in a word, they are monstrosities but they are without spores.
As soon as bacteriologists turned their attention more closely to the subject it was found that the spontaneous souring of milk was not always caused by the same species of bacterium. Instead of finding this Bacillus acidi lactici always present, they found that quite a number of different species of bacteria have the power of souring milk, and are found in different specimens of soured milk.
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