GLOSSARY 417 



Cap'illaries (Lat. capillus, a hair) : minute tubes which connect arteries with 



veins. 

 Capillar'ity : a phenomenon shown by hquids rising in fine tubes. 

 Carbohy'drate (Lat. carbo, coal ; Gr. hydor, water) : a class of nutrients com- 

 posed of carbon, oxygen, and hydrogen, having the oxygen and hydrogen 



in the same proportion as water. 

 Car'bon (Lat. carbo, coal) : an element found in all organic compounds. 

 Carbon dioxide : a gas, a product of the oxidation of carbon. 

 Cell : the structural and physiological unit in plant and animal bodies. A 



small mass of protoplasm in most cases inclosed in a cell membrane and 



usually containing a nucleus. 

 Cell membrane : the delicate living covering of a cell. 



Cell sap : water, with materials in solution, found in the vacuoles of plant cells. 

 Ceriulose ': a dead substance found in the walls of plant cells. 

 Cerebellum (Lat., diminutive of cerebrum) : part of the brain between the 



cerebrum and the medulla oblongata. 

 Cer'ebnim (Lat. cerebrum, the brain) : the anterior part of the brain. 

 Chemical compound : a substance formed by the combination of chemical 



elements. 

 Chemical element : a simple substance ; one which cannot be formed by the 



combination of simpler substances. 

 Chi'tin (Gr. chiton, a tunic) : a hard, nitrogenous substance present in the exo 



skeleton of insects. 

 Chlo'rophyll (Gr. chloros, grass green ; phyllon, a leaf) : the green coloring 



matter of plants. 

 Chlo'roplasts : small bodies of protoplasm which contain chlorophyll. 

 Cho'roid : the middle coat of the eye. 

 Chro'mosome (Gr. chroma, color ; soma, body) : a deeply staining body in the 



nucleus of a cell, supposed to carry the determiners of hereditary qualities. 

 Chrys'alis (Gr. chrysos, gold) : the uncovered pupal stage of butterflies. 

 Cil'ium (Lat. cilium, an eyelid with hairs growing on it) : a tiny hairlike thread 



of protoplasm extending from a cell. 

 Cloa'ca (Lat. cloaca, sewer) : the common cavity into which the digestive, 



urinary, and reproductive systems open in some kinds of vertebrates. 

 Coc'cus (Gr. kokkus, berry) : a ball-shaped bacterium. 

 Cocoon' : a silky covering around a pupa ; the egg-case of spiders. 

 Commu'nicable disease : a disease that can be passed directly from one person 



to another. 

 Compound eye : an eye made up of many simple eyes or ommatidia. Arthro- 

 pods have compound eyes. 

 Conjuga'tion (Lat. cum, together with ; jugare, to yoke) : the temporary 



union of two sex cells of equal size, with a fusion of nuclei and interchange 



of nuclear material. 

 Connective tissue : collections of cells which support and connect other tissues. 

 Contrac'tile vac'uole : a small vesicle, found in the cytoplasm of many proto- 



