Consumption is caused by the growth of certain microorganisms in the tissue of our bodies. These micro-organisms grow in us in the same way as wheat, timothy and clover grow in a field. The chief of them is called the tubercle bacillus. Without it consumption cannot take place, but it alone cannot produce all the phenomena which we know as consumption. Some of the others which help to make up the disease are the streptococcus and the staphylococcus. The word consumption means burning up, and was given to the disease because the person who is affected wastes away as though he were consumed. In olden times the disease was not recognized until the patient was on the brink of the grave. The stages which lead up to this fatal termination were usually looked upon as other diseases and were known under other names. This relationship was not recognized until scientific men began to dissect the human body after death and carefully study the changes which had taken place. It was then that the word tuberculosis came into use. It was gradually substituted for the word consumption.