When the changes in the epithelia are only slight and secondary, it is spoken of as an interstitial (lying between) inflammation, which strictly speaking denotes confined to connective tissue, and is therefore a term not entirely correct. When the inflammation of the epithelia is severe and may lead to their partial destruction, it is called a parenchymatous inflammation; that is, one involving the soft cellular substance. There is still another variety, the suppurative, which is the most intense of all, and indicates the production of an abscess and the entire destruction of the tissue implicated. Beside these general grades of inflammation there are special sorts produced by specific micro-organisms. In all general inflammation we may expect to find such organisms, which in most cases belong to the class of micrococci, such as staphylococci and streptococci. In gonorrhea we have a special organism called the "gonococcus"; while in tuberculosis--a variety of inflammation in which the blood-vessels are completely destroyed and a change or degeneration called "cheesy" is produced, leading to the production of a tubercle--a rod-like bacillus is invariably found, the well-known and unfortunately too common tubercle bacillus. In syphilis--another special variety of inflammation--a specific micro-organism is also surely present, but of this microbe science has not as yet discovered the exact nature. The question of the origin of tumors or new growths is also an extremely important one; and it is undoubtedly true that many tumors arise where there was a previous inflammation, this being especially the case in tumors of the rectum. Why such a growth should arise in some cases and not in others is as yet unknown, though microbes are held by many to play an important rôle.