GLOSSARY 



[Only those terms are denned in this glossary which either are not explained 

 in the text, or are explained once and used again several pages beyond the 

 explanation.] 



Agametes : asexual reproductive cells which develop, without fertilization, into an 

 adult organism. 



Algae : the most primitive green plants ; they live in both fresh and salt water or 

 in moist locations. 



Amino acid : an acid in which a portion of the nonacid hydrogen has been re- 

 placed by a nitrogen-hydrogen combination. Many of the amino acids are 

 important products when proteids decompose. 



Amphimixis (from two Greek words, amphi, meaning "of both kinds," and mixis, 

 meaning "a mingling") : the union of the germ-plasms of two individuals in 

 sexual reproduction. 



Amphimonad (from two Greek words, amphi, meaning of both kinds," and monad, 

 meaning "alone," or "unit") : a technical term used in protozoology to desig- 

 nate a simple animal-flagellate with two equal flagella. 



Amphinucleus : a new nucleus formed by the fusion of two nuclei, each of which 

 had but half the normal number of chromosomes. 



Antibody: any of various bodies or substances in the blood which act in antagonism 

 to harmful foreign bodies, such as toxins. 



Antitoxin : any of certain complex soluble chemical compounds occurring in the 

 blood, either normally or under certain special conditions, and having the power 

 of neutralizing some specific poison — especially a compound capable of neutral- 

 izing one of the poisons produced in the body by pathogenic bacteria, and hence 

 conferring immunity, or conducing towards recovery, from the disease caused 

 by the bacteria. 



Anus (adjective, anal) : the posterior opening of the alimentary canal, or in 

 protozoa, a permanent pore in the cell through which indigestible remains are 

 voided. 



Arboroid : in the form of a tree or bush ; used in protistology to indicate a 

 branching type of colony. 



Atrophy (from the Greek, meaning "not to nourish") : a stoppage of development 

 of a part or organ (often followed by loss in size or even complete disappear- 

 ance) incidental to the normal development or life of an animal or plant. 



Basal body : a granule in the cell from the substance of which a flagellum or 

 cilium grows. 



Carbohydrate : any of a group of neutral compounds, including the sugars, 

 starches, celluloses, etc., composed of carbon, hydrogen, and oxygen, and char- 

 acterized by containing six, or a multiple of six, carbon atoms, combined with 

 hydrogen and oxygen in the proper proportion to form water. 



Catalysis (plural catalyses) : the speeding up of a reaction which has been in- 

 duced by the presence of a substance, called the catalytic agent or catalyzer, 

 which itself appears to remain unchanged. Originally the term was applied to 

 decompositions only. 



Catalyst: a substance which causes the break-down of other substances. 



Catenoid : like a chain ; linked together in such a way as to give the appearance 

 of a chain. 



Caudal : like or pertaining to a tail. 



Cellulose : an inert substance constituting the chief part of the solid framework 

 of plants, of ordinary wood, linen, paper, etc. It is also found to a slight extent 

 in certain animals. It is a carbohydrate of the same percentage composition as 

 starch, and is convertible into starches and sugars by the action of heat and 

 acids. When pure it is a white mass without crystals. 



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