Helohacter 



172 



Helobacter, nitrogen fixation, V. 267. 



Hemp (Chanvre), IV. 274. 



Hen (Poule), II. 344. 



Herbarium material, preparation, IV. 12. 



Hereditary constant modifications : caus- 

 edbynutrition, 1.412; 11.200,201, 251, 

 292; III. 177-181; IV. 338; V. 34, 35, 

 178-181, 186, 192, 193, 281, 286, 287. 



— caused by parasites, I. 10, 14, 15, 26, 

 130. 



Hereditary constant variants, II. 201, 

 247, 251, 292; III. 165, 265; IV. 38, 40, 

 46, 47, 76, 235, 333-340; V. 25, 29, 

 155, see also: Mutants. 



Hereditary units, III. 228, 229; V. 248- 

 254-258, see also : Genes. 



Hereditary variability, concept, IV. 40, 

 46; V. 25. 



Heredity: complex factors, V. 214, 250- 

 255, 256-258. 



— enzyme theory of, V. 40, 248-254- 

 258. 



— multiple factors, V. 39, 40, 214. 



— mutation and variation of asexual 

 organisms, III. 165; IV. 37-47, 235; 

 V. 28-30, 40, 67, 73-75, 84, 214, 248- 

 254-258. 



Heterobolism, IV. 21. 



Heterodera radicicola, description, II. 141 



-142*. 

 Heteroecism, III. 202, 203; IV. 133, 136. 

 Heterogamy, V. 65. 



Heterogeneous cell partition, IV. 43-47. 

 Heterogenesis: I. 150-155, 174, 175, 190, 



201,236, 237; II. 124, 125; III. 199- 



209-231; IV. 133-138. 



— biological significance, III. 200. 

 Heteromorphism : of Coniferae, II. 283- 



292. 



— of galls, I. 2, 24-26, 39, 128, 129, 

 137. 



Heteroplasism, I. 10, 11. 



Heterostyly, V. 77, 80, 85. 



Heterosynthesis, V. 231-242. 



Heterotrophic forms of autotrophic and 

 oligotrophic bacteria, V. 178, 179, 187- 

 193, 281, 284, 285, 287, 288. 



Hêtre : see Beech. 



Hibernation by adventitious buds, II. 57, 

 64. 



Hieracii wasp, oviposition, I. 165. 



Hippuric acid, decomposition, IV. 79. 



Hirse: see Millet. 



Hoef blad : see Coltsfoot. 



Hommel: see Humble bee. 



Homogentisinase, V. 114. 



Homogentisic acid, decomposition by 

 Microspira tyrosinatica, V. 115. 



Honey dew, IV. 275. 



Honigklee; see Melilot. 



Hoorn van Judea, I. 37. 



Hormidium parietinum, occurrence, III. 

 23. 



Hornbeam (Charme, Hainbuche), IV. 

 262; V. 78. 



Hoverfly (Zweefvlieg), I. 83. 



Huitre : see Oyster. 



Humble bee (Bourdon, Hommel, Hum- 

 mel), II. 126; V. 72, 241, 260. 



Hummel: see Humble bee. 



Humates, preparation, VI. 25. 



Humus: favourable action of colloidal 

 silicates in, V. 180. 282; VI. 22, 24, 25. 



— formation, IV. 13-19, 250, 252, 254, 

 255; VI. 6. 



Humus soil, few root nodules in, II. 



163; V. 264, 265; VI. 22. 

 Hyacinth (Jacinthe), I. 98, 104, 105, 



116, 285. 309, 321. 

 Hybrids: I. 401-408, 415-426; II. 189; 



IV. 48, 52; VI. 81, 85. 



— sterile, I. 360, 406-408. 416-426; VI. 

 82, 85. 



Hybridisation: experiments, I. 263. 359- 

 366, 401-408, 411, 412, 415-426; II. 

 127, 189, 290; III. 162; V. 26,28, 67; 

 VI. 82-85, see also: Variation. 



— influence on the formation of adven- 

 titious buds, II. 42, 44, 101. 



Hydra: chlorophyll of, II. 229-233, 304- 

 312; III. 21. 22; V. 288. 



— red pigment grains, II. 233, 306. 

 Hydra viridis, relation between the zoo- 



chlorellae and Chlorella vulgaris, II. 



229-231-233, 304-311; III. 22; V. 288. 

 Hydrobios, V. 139. 

 Hydrogen : as an energy source for che- 



mosynthetic carbon dioxide assimila- 



tion, V. 137, 231. 



— oxidizing bacteria, IV. 379; V. 137, 

 231. 



— peroxide, reduction by microorgan- 

 isms, II. 201, 246, 258; III. 43; IV. 

 59, 285; V. 108, VI. 79. 



— predominant gas in fermentation, 



III. 15, 95, 96. 



— production by Aerobacter, III. 346; 



IV. 28, 29. 33, 34, 36. 55, 146. 159. 283. 



— production by Granulobacter, III. 89. 

 90; IV. 143, 150, 257; V. 232. 



