INDEX. 



Wiesner 



on heliotropism of dorsiventral 

 shoots, 443 

 on heliotropic effect of light, 380, 



on heliotropic effect of rays of dif- 

 ferent wave length (Fig. 50), 433 

 on heliotropism of leaves, 444 

 on negatively heliotropic organs: 

 their growth in darkness, 440 

 on nutation, 368 



on organic acids in etiolated plants, 

 268 



on photochemical induction, 263 

 on photomechanical induction, 435 

 on physiological significance of 

 transpiration, 116 

 on resin, 232 



on reversal of heliotropic pro- 

 perties, 429 



on substances forming latex, 168 

 on transpiration as affected by light, 

 109, no 



Will, on peptic ferment, 190 

 Williamson, on excretion of water by 



Caladium, 92 



Wilson, on exhalation of carbon di- 

 oxide, by plants in light, 260; by 

 seedlings in absence of free oxygen, 

 200 



Wittwer, on absorption of carbon di- 

 oxide by leaves, 82 

 Woad, 239 

 Wolf- 

 on absorption of asparagin by roots, 

 124 



on excreta of plants, 224 

 on de Saussure's law of absorption, 

 58 

 Wolff 



on ash of, Buckwheat, 64, 65; 

 hay, etc., 60 



on potash in plants, 132; on sili- 

 con, 137 



von Wolkoff, on absorption of oxygen ; 



by plants, 198; by seedlings, 76, 260 



Woodhouse, on absorption of nitrogen 



by plants, 85 



Woodward, on transpiration, 104 

 Woronin, on reproduction of Botry- 



dium, 607 

 Woronin's hypha, 624 



Wortmann 



on destructive metabolism, 292 



on diastatic ferment in Bacteria, 

 189, 192 



on evolution of carbon dioxide by 

 seedlings, 200 



on hydrotropism, 478 



on nutation, 368 



on thermotropism, 434; of plas- 

 modia, 528 

 Wunschmann, on glands of Nepenthes, 



247 

 Wurtz, on peptic ferment (papai'n), 190 



Xanthin, 221 

 Xanthophyll, 241 

 Xylaria, 624 



Yeast (Fig. 2), 3; fermentative action 

 of, 208; growth of, in Pasteur's 

 solution, 3; in water, 4; potential 

 energy of, 5 ; reproduction of (Fig. 

 2), 3, 602 



Yucca filamentosa, positive geotropism 

 of rhizome of, 458 



Zacharias 



on the chemistry of sexual cells, 

 669 

 on nuclei'n, 27 



Zantedeschi, on heliotropic effect of 

 rays of different wave-lengths, 433 



Zimmermann, on induction of dorsi- 

 ventrality in gemmae of Marchantia, 

 426 



Zoospores, 603; influence on move- 

 ments of, age, 526; amount of water 

 of imbibition, 524; concentration of 

 solution of, 524; free oxygen, 297, 

 522, 526; light, 522; direction of 

 incidence of rays (phototaxis), 525; 

 of intensity (phototonus), 525 



Zoospores, 603; influence on movements, 

 of solutions, 529; of light, 523, 525; 

 of temperature, 297, 522, 526 



of Haematococcus (Fig. i), i, 6, 

 605; contractility of, 7; irritability 

 of, 7; phototaxis of, 524 



Zygnemeoe, reproduction of, 602, 612 



Zygomycetes, reproduction of, 617 



Zygospores, 607, 613, 617 



Zymogen, 193 



CAMBRIDGE : PRINTED BY C. J. CLAY, M.A. AND SON, AT THE UNIVERSITY PRESS, 



