Sarcina.—Literally, a bundle. Applied to bacteria grouped in bundles or packets.
Septic.—Putrefying or decomposing; infected by pus-producing bacteria.
Sequela.—A disease or unhealthy condition following another disease or unhealthy condition.
Serum.—The fluid which separates from the clot after blood has coagulated; especially, that containing an antitoxin.
Sewage.—Any substance containing urine or fecal matter; also, the substance which passes through sewers.
Spirillum (pl. spirilla).—A variety of bacteria having spirally twisted cells.
Spore.—A resting stage, characterized by great resistance, into which certain germs enter when conditions become unfavorable for their growth.
Staphylococcus.—A variety of bacteria that group themselves in masses resembling bunches of grapes.
Sterile.—Free from living germs; aseptic.