In this article the superficial types of infection, such as furuncles and carbuncles, will not be considered; only the deeper types of infection will be discussed. These I have divided into five classifications. First, there are acute suppurative conditions in the neck secondary to infections elsewhere. Many of these originate in some infection about the mouth, although they may come from infection about the scalp or face and occasionally from more distant points. They may develop by metastasis or by direct extension. The second type is known as woody or ligneous phlegmon, a condition which is probably secondary to infection elsewhere and in which there is marked induration but in which suppuration never occurs. In the third group are infections due to certain specific causes, and in this group are tuberculosis, syphilis, actinomycosis, blastomycosis and a rare condition, tularemia. The fourth group consists of infected cysts and