Pigment formation 



Pigment formation : in symbiosis, V. 112, 

 113, 280. 



— influence of salts of organic acids, 

 IV. 1 14, 119, 122, 124, 143, 152; VI. 22. 



— of acetic acid bacteria, V. 8, 9. 



— of Actinomycetes, IV. 13-22; V. 111- 

 113, 115, 188, 280. 



— of Azotohacter, IV. 114, 143, 152; 

 VI. 5. 



— of yeast, II. 222, see also: Yeast, 

 chromogenous. 



— of hair and skin, V. 6, 111. 

 Pine (Den, Pin), IV. 262; VI. 44. 

 Plaice (Scholle), V. 58. 



Planosarcina ureae : motile sporogenous 

 sarcina, IV. 87, 95*-97, 103*. 



— resistance to alkali, IV. 97. 



Plant louse (Bladluis, Blattlaus), I. 35, 



142; III. 55. 

 Plant pathology: I. 8; II. 289, 290, 292; 



III. 162. 



— galls, I. 1-80, 127-282, 386-400; II. 

 1-6, 123-137; III. 199-232; IV. 133- 

 138. 



— gummosis, I. 125-126, 321-357; IV. 

 267-277, 311, 312; V. 168-177. 



— Nematodes, I. 283-291 ; II. 139*-143*. 



— suncracks of trees, VI. 59, 60. 



— virus, III. 296-312, 323-344; V. 137- 

 139; VI. 16-19. 



Plasmic streaming, II. 10. 

 Plasmodiophora disease, I. 13; II. 3-5. 

 Plasmolysis, does not cause autofermen- 



tation, V. 165. 

 Plastic aequivalent, II. 252, 253, 257, 



262; III. 7; IV. 60, 244, 295-297; V. 



19, 232, 233, 234, 242, 273. 

 Plastic food, II. 337, 339, 244, 245. 

 Plate: manganese, V. 141-142. 



— malate, preparation, IV. 299. 



— silica, preparation, III. 190; IV. 

 128, 184, 239, 240; V. 180, 181, 284; 

 VI. 72. 



— yeast water urea, preparation, IV. 

 84-85; V. 246; VI. 20. 



Plate method: II. 164, 294, 308; III. 2, 

 44, 261 ; IV. 239; V. 6, 7, 37; VI. 10, 71. 



— ammonium magnesium phosphate — , 

 demonstration of nitrite formation, V. 

 185. 



— chalk, III. 1-5, 186, 189, 190; V. 185; 

 VI. 71. 



— chalk, and other metal carbonate, 

 III. 3, 4; V. 185. 



— chalk sulphur, V. 281-288. 



Plate method : elimination of condensa- 

 tion droplets, II. 164, 187*; IV. 117, 

 147, 335; V. 44, 187; VI. 4. 



— negative, V. 284. 



— starch, III. 92, 117. 

 Pleomorphism, III. 182; IV. 39; V. 74-76, 



84, 287. 



Pleonts, V. 74-76, 84. 



Pleospora gtimmipara: causing the pro- 

 duction of gum arabic, 1. 345-349-355. 



— Coryneum form, I. 349, 352. 



— diagnosis, I. 350, 356*. 

 Plerome-peribleme theory, II. 14. 

 Pleurococcus vulgaris: cultivation and 



description, III. 293-295. 



— occurrence, II. 227; III. 23. 



Plum (Pruim, Prunier), I. 58, 125, 325, 

 326, 330, 332, 335, 336, 338, 339, 341 ; 



IV. 268, 269, 275, 276; V. 168, 169, 

 172, 176. 



Poa, galls, cultivation of normal plants 



from, I. 397-400; II. 129; V. 256. 

 Pockenkrankheit, III. 310, 323. 

 Poirier: see Pear. 

 Pois : see Pea. 

 Poisons: influence of, IV. 271-273, 315; 



V. 166, 169, 170. 



— influence on yeast, IV. 315; V. 166. 

 Polarisation of the light by colloids, IV. 



346; V. 92, 197,' 238. 

 Polarityrll. 39, 40, 99. 



— of the sap flow, II. 9. 

 Polymorphism : I. 24-26, 129, 410; II. 



286, 290; III. 180, 264; IV. 40. 



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

 137. 



— (transformation) of Saccharomyces 

 sphaericMs, III. 174-180-182; IV. 40. 



— of the separate flowers of Dauciis 

 carota, I. 410, 411. 



— of Yeasts, III. 264, 265. - 

 Polytrophic forms of oligotrophic bac- 

 teria, V. 178, 179, 187-193, 210. 



Poma sodomitica, I. 19. 



Pomme de terre : see Potato. 



Pommier: see Apple. 



Populations, V. 36-38. 



Porselein: see Purslane. 



Potato (Aardappel, Kartoffel, Pomme 

 de terre), I. 15, 83, 90, 91, 93, 326, 

 328, 329, 334, 340, 344, 361; III. 137, 

 139, 187; IV. 164, 167, 169, 177, 178, 

 343; V. 21, 22, 98, 108, 115, 149, 151, 

 153, 195, 196, 197, 198*, 275, 276. 



Potato bacteria, II. 299; IV. 216. 



