In the first place, bacteria require for their best and most rapid growth the proper temperature, moisture and media relations. By this we mean that the temperature should be moderately warm, ranging from about forty to one hundred degrees Fahrenheit, the optimum being about the body temperature 98.6 degrees Fahrenheit or 37 degrees on the centigrade scale. With this optimum temperature, the element of moisture should always be present, as we find that nothing in nature will germinate without the necessary moisture. Then the bacteria must have the proper media, meaning that they must have the right substance on which to grow. Inasmuch as the cause of putrefaction is the host of putrefactive bacteria which abound trying to satisfy their own nutrition, and since these bacteria require a moderately warm and moist media on which to grow, it is only natural that putrefaction and decomposition should occur much more rapidly in warm moist climates than in dry cold climates. In regard to exposure we learn that certain putrefactive bacteria are aerobic in character, i. e., that they need a great quantity of oxygen for their growth, and for this reason a body in water or buried in the earth does not decompose as rapidly as one exposed to the air. But although they do not decompose as rapidly yet we find that they do decompose in time. This is due to the fact that there is another class of bacteria, called anaerobic, i. e., which do not need oxygen for their growth. In the case of the body in water these anaerobic bacteria exist and develope slowly in the alimentary tract, and eliminate gases sufficient to bring the body to the surface, where the aerobic bacteria enter, and putrefaction progresses much more rapidly. The starting point of decomposition is usually at the seat of the disease the subject had before death, but it soon spreads to all the various tissues of the body. Putrefaction is always accompanied by a great amount of odor, which is caused by the generation of gases the result of bacterial action. The obnoxious gases, offensive to the smell are sulphureted hydrogen, nitrogen, carbonic acid and ammonia. The material actually present when the body is actually decomposed has been determined as being water, nitrogen, methane, carbon dioxide, etc. _Treatment by the Embalmer._—Putrefaction always means that there is present a great amount of putrefactive bacteria and if you are to arrest this condition you must resort to the most thorough embalming. By placing some preservative fluid in the arteries and having a thorough circulation all the tissues of the body can be reached and hence the complete destruction of those bacteria causing the putrefaction.