The following is a report of the study of a number of sick hogs from which streptococci were isolated, together with an attempt to evaluate the significance of such microorganisms in diseased swine tissues. The hogs examined were from scattered herds, largely under 8 weeks of age. In some instances nothing was known of the condition of the droves of hogs concerned, either before or after the examinations. In others there was a fairly good history of the condition of the herd and the death losses. In general the cases may be divided into those in which the streptococci were present throughout the body tissues and those in which the infection was confined to the brain and its coverings or largely so. To obtain an understanding of the disease condition encountered in the various herds, some description of individual cases is given
