INDEX AND GLOSSARY 



145 



a sexual cell are the ids, viii, 

 23, 33. 



Idioblasts, Hertwig's name for 

 hypothetical ultimate units 

 of living matter, 22, 32 ; the 

 ultimate units of living 

 matter, according to De 

 Vries, 22. 



Idioplasm, as opposed to germ- 

 plasm, which is the nuclear 

 material of gerin-cells ; idio- 

 plasm is the nuclear material 

 of tissue-cells, xi, 38. 



Immortality, definition of, 82 ; 

 of germ-cells, ix ; of uni- 

 cellular organisms, 17 ; of 

 germ-cells, 80. 



Individuality of cells, 115. 



Invagination, the infolding of 

 a layer of cells, as, for 

 instance, in the transforma- 

 tion of a blastosphere into a 

 gastrula, xvii. 



Isotropism, explained in foot- 

 note, 33. 



K 



Karyokinesis, a complicated 

 process of nuclear division, 

 xiv. 



Katabolism, the formation of 

 less complex chemical bodies 

 by the agency of protoplasm, 

 86. 



Labile, unstable, constantly 

 changing, 38. 



LANDOIS, experiments on trans- 

 fusion of blood, 75. 



LEIBNITZ, on immortality, 82. 



LOEB, on heteromorphoses, 49 ; 

 on plasticity of animals, 117. 



M 



MAUPAS, experiments on sex 

 of rotifers, 123. 



Melons, determination of sex 

 by temperature, 124. 



Mesoblast, in the development 

 of the cceloniata, or three- 

 layered multicellular ani- 

 mals ; a third set of cells, 

 themesoblast, arises between 

 the epiblast and hypoblast, 

 xviii. 



Monsters, relation of, to divi- 

 sion of egg-cell, 63. 



Mosaic theory of Eoux, 56. 



Morphoplasrn, the general 

 protoplasm of a cell, 35. 



Multicellular organisms, those 

 in which the body is com- 

 posed of many cells, spe- 

 cialized in different direc- 

 tions ; cell- division in, 43. 



Mus, experiments on grafting 

 among mice and rats, 74. 



Myxomycetes, sometimes 

 called ' slime fungi,' a group 

 of low organisms, consisting 

 of creeping masses of proto- 

 plasm with many nuclei, 

 33. 



N 



NAEGELI, biological units, 30 ; 

 cross-fertilization and graft- 

 ing compared, 69 ; heredity, 

 92 ; environment in develop- 

 ment, 104 ; on plasticity of 

 plants, 119 ; on specific 

 characters of eggs, 134. 



Nais, regeneration in, 47. 



Notochord, formation of, from 

 unusual cells, 117. 



Nucleus, a specialized portion 

 of the protoplasm of cells, 

 different in chemical and 



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