There are three types of bacteria: the rod or bacillus, the sphere or coccus, and the spiral or spirillum, all so named because of their shape. They divide by what is known as fission, each cell dividing into two and so on. When the conditions are favorable this division may take place as often as every thirty minutes. They may be produced artificially in a proper culture medium. It is generally supposed by the layman that the bacteria are very hardy little creatures and will develop in the body and cause dis-ease under the least provocation. This, however, is quite erroneous for they are very delicate and their propagation is difficult. The temperature and moisture must be exactly right and they must have just the proper kind of food or they will not multiply. They will live in an environment, sometimes for a great length of time, that is not suitable for propagation. Diphtheric germs are found in the throat of the average person. These germs, however, will not multiply nor develop until the tissues of the throat are depleted. The tissues then become pathological and form food for the bacteria, but even then they will not develop unless the temperature and moisture are exactly right. Bacteria multiply very rapidly when there is waste material in the tissue of the throat which furnishes food and when the environment is conducive to their development. The tissues weakened by the decrease in the flow of mental impulses are not able to expel the germs and they accumulate, not as the cause of dis-ease, but as a result of dis-ease. The bacteriologist examines a culture from the throat of the patient and because he finds the germs present he says the germs cause the dis-ease, since no other cause is known; strange to say, however, when the patient is adjusted and the tissues become normal it is not necessary to kill the germs. They will starve to death and Innate will excrete them. Bacteria are found everywhere and in almost everything. In food, water, on the walls and floors, and in the pores of the skin. All life is due to the action of these bacteria. The action of the germs soon produce fermentation and putrefaction of dead animal tissue and of vegetables, thus reducing them into simpler elements which furnish nourishment for plant life. The plants furnish food for animals and man, and thus we have what is known as the food cycle. So we see that vegetation is dependent upon bacterial action for its supply of food. If the bacteria were all destroyed there would soon be an end of food and plant life would die because of starvation. If there was no plant life the animal kingdom would be robbed of its food supply. Thus we see the important function performed by the bacteria.