536 THE LAWS OF HEREDITY 



DARWINIAN ; a term sometimes used to designate that school of evolutionists which denies 

 the transmission of acquirements, and sometimes to designate the school which supposes 

 that evolution is founded, not on mutations, but on fluctuations. 



DAUGHTER-CELL ; see cell. 



DEDUCTION ; the chain of reasoning, the inverse process to induction, by means of which we 

 pass from a consideration of general notions to a consideration of particular facts. It is 

 most useful when employed to test the correctness of inductions and bring within their 

 range facts not previously included. 



DEVELOPMENT ; the growth or unfolding of the individual from the germ. 



EMBRYO ; the individual in his earliest stages of growth after development from the ovum. 



ENDEMIC disease ; strictly speaking a local malady which has no tendency to spread. 

 Usually, however, the term implies the continuous presence of a disease in a locality. 



ENZYME ; a ferment secreted by living cells. 



EPIDEMIC ; a term applied to a considerable outburst or increase of a disease. 



EVOLUTION ; an adaptive change undergone by a race. 



EXCRETION ; a term applied both to the act of eliminating waste or used up material from 

 the organism and to the waste material itself. 



FERTILIZED ovum ; see cell. 

 FLUCTUATION ; an unstable variation. 



FCETUS ; the individual in that stage of development that intervenes between the embryonic 

 condition and birth. 



GAMETE ; a germ-cell before conjugation. 



GERM-CELL ; see cell. 



GERM-PLASM ; see cell. 



GERM-TRACT ; see cell. 



GERMINAL ; pertaining to the germ-cell, or having origin in the germ-plasm. 



HAEMOPHILIA ; a disease or state in which the blood lacks coagulating power. 

 HEREDITY ; the organic relation between progenitors and descendants. 

 HEREDITARY tendencies ; see cell. 

 HERMAPHRODITE ; see cell. 



HYBRID ; an offspring or descendant derived from the union of individuals belonging to 

 distant species. 



HYPOTHESIS ; an inference not yet proved to be true. 



INBORN or innate ; a term employed to designate characters which are supposed to differ 

 from acquirements in that they are especially rooted in the constitution of the individual. 

 Really it designates traits that develop under stimuli other than use and injury. 



INDIVIDUAL ; see cell. 



INDUCTION ; the process of thought by means of which we found general notions on a 

 consideration of particular facts. Thus, having observed that offspring recapitulate the 

 parental development, we reach through induction the notion that they recapitulate the 

 life-history of the race. 



INHERITABLE ; a term used to designate characters that arise under a stimulus other than 

 use or injury. Really no characters are inheritable, or all are equally inheritable. 



LAMARCKIAN doctrine ; the doctrine that offspring tend to reproduce miraculously under 

 the stimulus of nutriment traits which evolution fitted progenitors to acquire under the 

 stimulus of use or injury. 



LARVA ; an insect in that stage of development which precedes the final stage. 



LAW, natural ; an established theory ; a description of a uniformity in the sequence of events 

 the actual existence of which has been proved. 



LIFE-HISTORY ; the stages of the evolution of the race. 



MATERNAL impression ; a term having origin in the popular belief that maternal mental 

 impressions are apt to produce analogous physical peculiarities in the child. 



