sodium chloride. Common table salt.

sodium hydroxide. Caustic soda. Used for its caustic effects.

sodium sulphate. Colorless crystals. Glauber’s salt; a purgative.

sodium urate. The substance found in gouty nodes; chalk-stone.

spasm. An involuntary convulsive muscular contraction.

spirillum. A genus of spirillaceae containing rigid cells with polar tufts.

spirochaeta pallida. The specific organism of syphilis.

splint. An apparatus for fixating a joint.

spontaneous. Occurring without external stimulation.

spores. Reproductive bodies of cryptogams.