246 GLOSSARY 



SYNAPSIS. The union of maternal and paternal chromosomes prior to 

 the maturation divisions. 



TAXONOMY. The science of classification. 



TERTIAN MALARIA. Chill and fever on every third day. Caused by 

 Plasmodium vivax, a protozoan parasite. 



TETRAD. Bivalent chromosomes which appear to be 4-parted in the 

 maturation divisions. 



TISSUE. An aggregate of similar cells or cell products having the same 

 function. 



TOXIN. A poison; usually employed to indicate products of protein break- 

 down during the metabolic processes. 



TRACHEAE. As used here, the air-holding tubes of insects and allied forms. 



TRICHOCYST. One of the minute hair-like bodies developed in the cortical 

 protoplasm of an infusorian. 



TRYPSIN. A proteolytic ferment capable of rapidly digesting albumins. 



TYPHLOSOLE. A fold of the intestine of certain annelids and other inverte- 

 brates, formed by the inturning of the wall of the intestine along the 

 dorso-median line and projecting into the intestinal cavity. 



UREA. The final product of protein decomposition in the body, forming 

 the chief solid constituent of the excretory fluid of many animals. 



VASCULAR BUNDLE. An aggregate of woody fibers, cellular ducts, and col- 

 umnar cells, found in vascular cryptogams and higher plants. 



VITAMINES. Substances of unknown chemical composition necessary for 

 nutrition of the body. 



XANTHOPHYLL. A yellow-green substance derived from cholorophyll. 



ZOOGLOEA. A mass of bacteria embedded in jelly of their own secretion. 



ZYMASE. The enzyme of yeast which causes the breaking up of sugar into 

 alcohol and carbon dioxide, or alcoholic fermentation. 



ZYMOGEN. Substance from which enzymes are formed by internal changes. 



