Morbific Agents
Morbific agents are those agents which are thought capable of producing dis-ease when introduced into the body. They are of vegetable or animal origin. Those of vegetable origin are classed under the general name of bacteria. The most important are named according to their form. Those of the spherical shape are known as cocci; the elongated, rod-like form, as bacilli; and those of spiral form, as spirilli. The streptococcus pyogenes, pneumococcus and gonococcus are illustrations of the cocci. The most common pathogenic bacilli are bacillus anthracis, bacillus tetani, bacillus typhosus, bacillus tuberculosis and bacillus influenzæ. The most usual spirilla are vibrio cholera asiatica, spirillum of relapsing fever and spirochæta pallida. Pathogenic action of germs upon the body may be mechanical, biological or chemical. The mechanical action is an interference with the physiological activity of the organs, causing stasis and hemorrhage. The biological action causes inflammation, infiltration and abscesses in the tissues. The chemical action is the result of the toxins formed by the action of the germs. This is by far the most important action.