304 MANUAL OF MICROBIOLOGICAL METHODS 



Sarcina (pL-ae), a regular cubical packet of cocci, resulting from cell 



division in three planes. Also, the genus of cocci forming such 



packets. 

 Saucer, a concave liquefaction of the medium, shallower than crateri- 



form. 

 Sheath, an envelope similar to a capsule (see above) but surrounding a 



filamentous organism. 

 Smooth, colonies with an even surface. 

 Spherical, globular. 

 Spindle{d), larger at the middle than at the ends. Applied to sporangia, 



refers to the forms called Clostridia. Also describes colonies, usually 



subsurface forms. 

 Spiral, a long, curved rod form of bacterial cell; a coiled cell. (Cf. 



Comma.) 

 Sporangium (pl.-ia), cell containing an endospore. 

 Spore, a reproductive cell of lower organisms ; in bacteria, usually same as 



endospore. 

 Spreading, growth extending much beyond the point or line of inoculation, 



i.e., several millimeters or more. 

 Stratiform, liquefying to the walls of the tube at the top and then pro- 

 ceeding downwards horizontally. 

 Streptococci, cocci in the form of a chain. 

 Strict aerobe, see aerobic. 

 Strict anaerobe, see anaerohic. 

 Subcutaneous, under the skin. 

 Subterminal, situated toward the end of the cell but not at the end, i.e., 



intermediate between the positions denoted excentric (see above) 



and terminal. 

 Syncope, loss of consciousness due to cerebral anemia. 

 Terminal, at the end of a cell, as a spore. 

 Thermal death point (TDP), temperature at which an organism is 



killed after exposure for 10 min. 

 Thermal death time (TDT), time required to kill an organism at a 



specific temperature. 

 Toxin, a poisonous substance of plant or animal origin. 

 Transient, lasting a short time, in contrast to persistent. 

 Translucent, allowing light to pass through without allowing complete 



visibility of objects seen through the substance in question. 

 Truncate, ends abrupt, square. 

 Turbid, cloudy. 

 Ulcer, an open sore. 



Umbonate, having a raised center; knoblike. 

 Undulate, wavy. 



