GLOSSARY 537 



MENDELISM ; a biological doctrine founded by Mendel. 



MICROBES ; unicellular animals and plants which cause infectious disease in higher types. 



MODIFICATION ; a term commonly used to designate a character which has resulted from use 

 or injury ; an acquirement. 



MONGREL ; the offspring or descendant of parents that were derived from distant varieties. 

 MONSTER ; an individual that diverges very greatly from the type of his race. 

 MOTHER-CELL ; see cell. 

 MULTICELLULAR ; see cell. 



MUTATION ; according to de Vries, a wide departure from the normal type, a ' sport ' ; 

 according to Punnett and others, a stable variation. 



MUTATION hypothesis ; the doctrine that evolution is founded on mutations. 



NUCLEUS ; see cell. 

 NUCLEO-PLASM ; see cell. 



OVUM ; see cell. 

 OVULE ; see cell. 



PANDEMIC ; a very wide-spread epidemic. 



PARASITE ; an organism that obtains its nutriment from the tissues of living beings. 



PARTHENOGENESIS ; see cell. 



PATHOGENIC ; disease-producing. 



PLACENTA ; the organ which connects a mother with her unborn child. 



POLLEN-GRAIN ; see cell. 



PROGRESSION ; an increase, due to variation, of one or more of the qualities of a character 

 e.g. size, complexity, power. 



PROTOPLASM ; the physical basis of life. 



RECAPITULATION ; the recapitulation (always with variations) by the individual of the 

 parental development and the racial life-history. 



REGRESSION ; the tendency displayed by the progenitors or descendants of exceptional 

 individuals to be nearer the racial mean. 



RETROGRESSION ; a decrease, due to variation, of one or more of the qualities of a character. 

 REVERSION ; a return to the ancestral type. 



SAPROPHYTE ; an organism that obtains its nutriment from non-living matter. 



SELECTION ; is of several kinds ; artificial, when man consciously chooses the progenitors 

 of a race : natural, when unconscious nature exercises the choice ; reversed, when the 

 selection " affects not increase of an organ, but decrease of it " ; germinal, when (as 

 has been supposed) the selection occurs among the units of the germ-plasm. 



SELECTIONIST ; an adherent of the doctrine that evolution is founded on the selection of 



fluctuations. 



SELF-FERTILIZATION ; see cell. 

 SEXUAL ; see cell 

 SOMA ; see cell. 



SOMATIC ; pertaining to the soma. 

 SPERM or spermatozoa ; see cell. 

 SPONTANEOUS ; a term used to designate alterations in the germ-plasm caused, not by 



external, but by internal conditions. 



TELEGONY ; a term having origin in the popular belief that if a mother has offspring by two 



mates, the children of the second father will exhibit the influence of the first. 

 THEORY ; an inference or hypothesis which has been proved to be true. 

 TOXIN ; a poison, offensive or defensive in function, secreted by a living being. 



