GLOSSARY 313 



Chromomeres. See Chromatin granules. 



Chromosomes. The dots, rods, rings, or other bodies that exist in definite 

 numbers in the nucleus and that derive their name from the readiness with 

 which they assume color under the various staining reagents employed by 

 biologists to bring out structural differences under the microscope. 



Chromatin granules. The minute granular masses of which the chromosomes 

 appear to be composed ; synonymous with chromomeres. 



Cross breeding. Synonymous with crossing. 



Crossing. The fertilizing of one species by the male of another species, 

 race, or variety. Synonymous with cross breeding. 



Cytoplasm. The cell contents that surround the nucleus. 



Degenerate. The individual which has inherited in strong degree the worst 

 characters of his race with few or none of the best, though he may have one 

 or more exceptional faculties. 



Determinant. Such an association of ids (Weismann) as may be able to fix 

 the character of a part in its development. 



Development. Progressive change ; specifically the appearance of racial 

 characters in the individual as growth proceeds. 



Differentiation. The appearance of distinctly differing organs and parts 

 during and after embryonic development. 



Dominant characters. See Characters, dominant. 



Dwarf. The individual in which the process of growth has been arrested 

 abnormally early. See Giant. 



Embryo. The fertilized ovum after growth and differentiation begin. 



Embryonic development. Growth and differentiation of the embryo. 



Environment. The conditions of life as a whole, both good and bad, that sur- 

 round the individual or the species, by which it may be either benefited or 

 oppressed, but with which it must live and compete. 



Eugenics. The doctrine that human beings should be well born by attention 

 in marriage to the well-known facts of heredity. 



Evolution. The theory that species originate by development from other 

 :nd preexisting species by means of more or less gradual modifications either 

 through crossing or the influence of the environment, or both; over against the 

 older theory that each species was specially and separately created, and that 

 it remains unchanged and unchangeable. 



Fetus. The more or less perfectly developed embryo before birth. 



Gamete. A reproductive cell either male or female. 



Genetics. The science of breeding from the standpoint of the transmission 

 f hereditary characters without rcgaird to the influence of environment. 



Germ plasm. Reproductive or sex cells in general, without reference to 

 sex. 



Germinal matter. Synonymous with germ plasm. 



Giant. The individual in which cell division and growth have proceeded 

 beyond the normal. See Dwarf. 



