208 GLOSSARY 



Encystment The grouping together within a resistant membrane 

 of forms or stages in the life cycle of organisms, or a resting stage 

 when conditions for life are unfavorable. 



Enzyme The products of life of organisms by which they digest 

 their foodstuffs. A substance capable of splitting others into simpler 

 ones without itself undergoing any change or entering into the new 

 product. Also called ferment. Related words: enzymic, enzymatic. 



Etiology Study of the cause of a disease and its transmission; 

 also the cause itself. 



Ferment (pronounced fer-ment) See Enzyme. 



Fermentation The breaking of sugars and starches (carbo- 

 hydrates) by bacterial ferments, with the production of carbon 

 dioxide, alcohols, and sometimes acids. Related words: to ferment, 

 fermentative. 



Genus Next to the lowest division of biological classification, 

 including members of the lowest division, species, among which 

 there are only slight differences. Members of a genus must be alike 

 in all important characters. See Species. 



Germination The progressive multiplication of the active adult 

 forms. 



Growth A word used to cover the appearance of a culture on 

 laboratory media, and sometimes used interchangeably with 

 culture. 



Host The body which carries a parasite. 



Immunity The resistance of the body to illness. See p. 65 for 

 kinds. Related words: to immunize, immunization, immune. 



Infective Any material carrying disease viruses. 



Inhibit Restrain, limit. 



Inject To put anything within the body; in this book it usually 

 means to put beneath the skin. 



Inoculate To put some infective material within the body; 

 usually used in experimental work upon lower animals. 



Inorganic Of the mineral world and not necessarily associated 

 with living matter; example, salt. See Organic. 



Isolate Used to indicate the procuring of germs from morbid 

 fluids or to the obtaining of a single kind, a pure culture, usually 

 by finding one type of colony. Related word : isolation. 



