Index 



513 



Natural selection, 467. 



Nemec, B., 507. 



Newcombe, F. C., 507. 



Newman, 148. 



Nitrates, 229. 



Nitrification, 233, 246 ; conditions 



of, 234. 



Nitrifying organisms, 233. 

 Nitrites, 229 ; soil, 233. 

 Nitrogen, content, 227 ; electric 



fixation, 245; fixation, 236; 



fungi fixing, 242 ; organisms 



fixing, 236; relation, 226; soil, 



228 ; sources of, 244. 

 Nobbe, 45, 147, 399. 

 Noll, 13. 



Nuclear division, 324. 

 Nucleus, 20. 

 Nutation, 502. 

 Nutrient solutions, 144 ; strength 



of, 146. 

 Nyctitropism, 504. 



O 



Oglevee, C. S., 462. 



Oliver, G. W., 491. 



Organic acids, 261. 



Organic food, 195. 



Organic matter, rate of production, 



216. 



Origin of varieties, 469. 

 Osborne, T. B., 279. 

 Osmoscope, 80. 

 Osmosis, 65 ; explanation of, 67 ; 



nutrient salts and, 73. 

 Osmotic pressure, 81 ; role of, 76. 

 Osterhout, W. J. V., 13, 71, 194. 

 Overton, E., 83. 

 Oxygen, in respiration, 285 ; and 



growth, 302. 



Paddock, W., 279, 407. 

 Paraffined basket, 163. 



Parenchyma, 25. 



Parthenocarpy, 369, 379. 



Parthenogenesis, 364. 



Pearson, K., 490. 



Peirce, G. J., 13, 248, 303, 507. 



Percival, 245. 



Perennials, food storage, 252. 



Periblem, 50. 



Pfeffer, W., 13, 34, 63, 83, 115, 168, 

 183, 225, 249, 279, 346, 380, 435, 

 503, 507. 



Pfeffer's solution, 146. 



Phosphorus, availability, 161 ; role, 

 171. 



Photosynthesis, 219 ; course of, 

 204 ; demonstration of, 205 ; fac- 

 tors, 204, 223, 224 ; rate of, 222. 



Phototropism, 497. 



Pieters, A. J., 399. 



Plasmolysis, 69, 80. ^ 



Plastids, 21. 



Plate, L., 492. 



Plerome, 50. 



Poisons, 436. 



Polarity, 310. 



Pollination, 350 ; secondary effects 

 of, 368. 



Pollock, J. B., 507. 



Population, 464. 



Potassium, pyrogallate, 221 ; role 

 of, 172. 



Potted plants, water supply, 127. 



Prazmowski, A., 248. 



Precipitation, 118; annual, 119. 



Precipitation membrane, 80. 



Prescott, S. C., 299. 



Price, H. L., 492. 



Proteins, 259 ; classes of, 260. 



Protoplasm, 17 ; irritability of, 31 ; 

 movement of, 29, 33 ; per- 

 meability of, 74, 82, 276. 



Pruning and growth, 326. 



Punnett, R. C., 493. 



Pure lines, 471. 



Puriewitz, 303. 



Purity of gametes, 484. 



