are no dominant and recessive characters but 

 a mixing of the two. 



blood count: count of red or white blood cells in 

 a small drop of blood. (White are counted 

 to diagnose infection; red for anemia.) 



botany: study of plants. 



brachydactyly (brak'i-dak'te-lee) : condition of 

 having short fingers or toes with two instead 

 of three bones in each. 



breathing: inhaling and exhaling of air in ani- 

 mals. 



breed: relatively homogeneous group of animals 

 within a species developed and maintained by 

 man. 



breed true: to have all the offspring show the 

 same character as the parent or parents 

 through the generations. 



bronchi (bron'kye) pi.: two branches of the wind- 

 pipe, one of which enters each lung. 



bronchial (bron'kee-el) tubes: tubes with many 

 branches in the lung leading from the bron- 

 chus; the finest branches of the tubes end in 

 air sacs. 



bryophytes (brye'o-fites) : members of the large 

 group or phylum of plants which includes the 

 mosses and liverworts. 



bud: in higher plants an outgrowth from the end 

 of the stem or from cells in the axils of the 

 leaves, containing undeveloped leaves and/or 

 flowers; in lower organisms a small out- 

 growth that forms asexually and develops 

 into a new organism; also applied to other 

 small structures, as taste buds. 



budding: form of asexual reproduction in some 

 lower organisms in which a small outgrowth 

 (bud) develops into a new organism; a kind 

 of grafting in which the scion is a bud. 



bulb: structure formed in some monocots, consist- 

 ing of a bud with fleshy leaves and a reduced 

 flattened stem, capable of producing a new 

 organism by vegetative reproduction. 



Calorie (kal'o-ree) : unit for measuring heat en- 

 ergy. The large Calorie (used to measure 

 heat energy released by living things or by 

 food) is the amount of heat required to raise 

 the temperature of 1000 grams (a little more 

 than a quart) of water one degree Centi- 

 grade. 



calorimeter (cal'o-rim'e-ter) : apparatus used to 

 measure the number of calories in foods or 

 other substances. 



calyx (kay'lix) : group of sepals in a flower; out- 

 ermost circle of leaf-like flower parts, usually 

 green in color. 



cambium (kam'be-um) : narrow cylinder of thin- 

 walled, actively growing cells between xylum 

 and phloem in dicot stems and sometimes 

 their roots. 



Cambrian (kam'bree-an) period: an early period 

 of the Paleozoic era in which trilobites and 

 many other aquatic animals flourished. 



canines (kay'nines) : when well developed, as in 



some mammals, teeth used for tearing flesh; 

 the eye teeth in man. 



capillaries (cap'ill-a-rees) : microscopic blood ves- 

 sels with very thin walls, located all over the 

 body; they receive blood from arteries and 

 give it to veins. 



carbohydrates (car-bo-hy'drates) : group of com- 

 pounds, such as starches, sugars, and others, 

 composed of carbon, hydrogen, and oxygen, 

 with the hydrogen and oxygen in the propor- 

 tion of two to one, as in water. 



Carboniferous (car-bon-if'er-us) period: a late 

 period in the Paleozoic era in which the coal 

 beds were formed. 



carnivores (car'ni-vores) : members of an order of 

 mammals that are chiefly flesh-eating, with 

 well-developed canines. 



carotene (care'o-teen) : yellow substance found 

 in some plants, such as carrots, which can be 

 changed to vitamin A in animals. 



carrier: person or other animal that carries germs 

 of a particulai disease without having the 

 disease and in some cases without ever hav- 

 ing had the disease. 



cartilage (car'til-aj) : firm, flexible connective tis- 

 sue in animals, often found making up part 

 of a bone and in some animals occurring in- 

 stead of bone; gristle. 



cattalo (cat'a-lo) : species produced by crossing 

 any of the domestic breeds of cattle with the 

 American bison (buffalo). 



Caucasoid (cau'kass-oyd) stock: one of the three 

 main stocks of living men; it includes, among 

 others, Nordics and Hindus. 



cell: a small, usually microscopic, mass of proto- 

 plasm, normally consisting of nucleus, cyto- 

 plasm, and cell membrane; all organisms 

 consist of one or more cells. 



cell body: part of the cell that is outside the nu- 

 cleus and inside the cell membrane. 



cell membrane: thin layer of thickened living mat- 

 ter which surrounds every cell; also called 

 plasma membrane. 



cell theory: all living things are made of cells and 

 the products of cells. This has been so well 

 established that it can be called the cell doc- 

 trine. 



cell wall: thick layer of lifeless material outside 

 the cell membrane of most plant and some 

 animal cells. 



cellulose (cell'you-lohss) : a carbohydrate found 

 in the cell wall of plant cells. 



central nervous system: the brain and spinal cord 

 in a vertebrate. 



centrosome: tiny protoplasmic body close to the 

 nucleus, mostly in animal cells; it seems to 

 play some part in mitosis. 



cerebellum (ser-e-bel'lum) : that part of the ver- 

 tebrate brain which lies back of the cerebrum 

 and in front of the medulla; it is concerned 

 with coordination of voluntary muscle move- 

 ments and equilibrium. 



585 



