When you began the study of inflamation in your sophomore year you were given a detailed description of the histopathological changes which occur throughout this defensive reaction of the body against an irritant. In that introduction to inflammation you became acquainted with the acute non-suppurative form of the process. From that first description it was easy and logical to go on to a detailed account of the alterations which occur in the tissues in chronic nonsuppurative inflammation. After that it was not difficult to add the special tissue reactions which appear in acute and chronic suppurative inflammation. After disposing of non-suppurative and supparative inflammation there remained a third type which called for special consideration. It was granulomatous inflammation. This type of reaction called for special handling because it appeared so different from the other two types.