COCCUS, in zoology, a genus of insects of the order Hetniptera, family Coccicke. See SCALE INSECTS; also COCHINEAL ; KERMES ; LAC /n Medicine.— Coccus is also the name of a family of bacteria characterized by their spherical form and consisting of a number of genera, all named for certain growth characters. Thus cocci that grow in chains are termed Streptococci in which group the virulent bac teria that cause blood-poisoning, septicwmia, and the organism of erysipelas are found; cocci that grow in pairs are termed diplococci. The diplococcus of pneumonia and the diplococcus of gonorrhcea are in this group. Others grow in bunches,— Staphylococci. The common organism of pus is Staphylococcus pyogenes aureus, by bacteriologists usually called S.p.a. Other spherical forrns are known as Micrococci, one of which group, the Micrococcus urea, is found in the urine as causative agent in sive urinary fermentation. Some forms of this
family group grow in packets. These are termed Sarcsnce. They are very abundant in the air, and are frequently associated with chronic gastric fermentations. A large number of different forms of this family are known, the greater majority of which are not pathogenic but very useful in agriculture and the arts, par ticularly in agricultural processes. As many as a hundred different species have been found in the air, and Chester has described 36 species of Streptococcus, 91 species of Micrococcus (Staphylococcus here included), 14 species of Savona., 3 species of Planococci, or movable cocci, and 3 species of Planosarcince. (See BACTERIA). Consult Chester, of De terminative Bacteriology.'