pneumococcus

(nu-mo-kok'us). Diplococcus pneumonias. Micrococcus lanceolatus. Streptococcus lanceolatus, the pathogenic microorganism of croupous pneumonia. Four principal types or strains of the p. are recognized, called respectively Type I, II, III, IV; Type III, called also P. mucosus, is distinguished quite sharply from the others Ijy morphological and cultural differences; Type IV contains a number of independent strains differing more or le from each other; pneumococci of this type are the ones usually found in the mouth, they are responsible for about 20 per cent, of cases of pneumonia and are the least virulent; Type III gives the lowest incidence in disease of all the types, but is the most virulent; Types I and II are responsible for about 60 per cent, of all cases of pneumonia. Type I giving the greater number.