INDEX 



293 



Galvanotaxis, as factor in develop- 

 ment of neuron pattern, 1 73 



Gradients, axial, 24. See also 

 gradients, physiological 



Gradients, excitation, 235. See 

 also Arc, reflex; Excitation, 

 Gradients, physiological; Trans- 

 mission 



Gradients, metabolic, 24. See also 

 Gradients, physiological 



Gradients, physiological : as prim- 

 ary factor in axiate pattern, 24; 

 as primarily superficial, 26, 32, 

 86; modifications of, during 

 development, 26; evidence for 

 existence of, 27; in relation to 

 structure and development, 27; 

 in relation to susceptibility, 32; 

 reversal of, 33, 243; in relation 

 to rate of penetration, 40; in 

 relation to reduction of KMnO 4 , 

 42; in relation to indophenol 

 reaction, 44; in relation to elec- 

 tric potential, 44; in relation to 

 respiration, 46; in axiate organs, 

 47, 220, 222; origin of new, 51, 

 70; obliteration of, 52; in limb 

 rudiment of Amblystoma, 52; 

 in animal egg, 54; in relation to 

 hereditary protoplasmic consti- 

 tution, 64, 129, 147; not pri- 

 marily concerned in evolution, 

 66; originating in excitation 

 gradients, 70, 77, 82, 235, 239; in 

 Amoeba, 86; in the literature, 

 87; as an integrating factor, 89; 

 in relation to differentiation, 90, 

 239; in relation to yolk develop- 

 ment, 94; in relation to domi- 

 nance and subordination, 97; 

 in relation to direction of trans- 

 mission, 97, 211, 213; in relation 

 to physiological isolation, 102; 

 in relation to localization of ner- 

 vous structure, 108, 144, 148, 151, 

 153; in relation to definitely 

 directed nerve growth, 112; ner- 

 vous system primary develop- 

 mental reaction to, 115; in 

 relation to independence and 

 dependence, 120; in relation to 



segmentation, 132, 254, 260; in 

 annelid development, 132; in 

 segmented animals in general, 

 135; nervous system as expres- 

 sion of, 144, 242; in relation to 

 nervous centralization, 147, 242; 

 in gasteropods, 148; in develop- 

 ment of axon, 1 68; in relation to 

 direction of axon outgrowth, 

 185; in outgrowth of dendrites, 

 193; in ctenophore plate row, 

 220; in axon, 226; in sessile 

 coelenterates, 243; in sponges, 

 243; in relation to development 

 of amphibian reflex arcs, 252; 

 in vertebrate development, 254; 

 in higher vertebrates, 259 



Harenactis: origin of new polari- 

 ties in, 52; bilateral tentacle 

 groupings in, 57; axial integra- 

 tion in, 248 



Heredity: in establishment of 

 axiate pattern, 49, 58, 59; gradi- 

 ent conception independent of 

 theories of, 66, 270 



Heteromorphosis: axial, as normal 

 feature of hydroid development, 

 34; axial, in Tubularia, 123; 

 axial, in Planaria, 126 



Hydroids: reversal of gradient in 

 development of, 33, 243; origin 

 of new polarity in, 52 



Inheritance, of physiological axes, 

 49, 58 



Inhibition: differential, 36; de- 

 velopmental results of, 37; 

 microcephaly as differential, 37; 

 cyclopia as differential, 38 



Integration, organismic: nature 

 of, 7, 15; possible quantita- 

 tive factor in mechanism of, 

 10 ; in relation to chemical 

 correlation, 13, 93; in relation 

 to excitation-transmission, 89, 

 107; nervous system chief organ 

 of, 89, 90, 108; in relation to 

 electric current, 90; following 

 physiological isolation, 105, 135; 



