114 Agkicultlfkal Expekiment Station, Ithaca, N. Y. 



Wollney shows that the water content* is less and the quantity of 

 carbohydrates greater the better the plants are lighted. 



One reason why shade plants when exposed to the direct light of the 

 sun may be injured is because the fonn and structure of the leaves 

 developed in the shade is different from that of plants in sunny places 

 as shown by Stahl.f Grosglick J has proved experimentally that such 

 difference is a natural adaptation to environment. 



Obstructed transpiration in conjunction with strong root pressure 

 produces much the same condition of tissues as is found in etiolated 

 plants. Ward says,|| "we may look on a shoot growing in a saturated 

 atmosphere as presenting all the chief features of one growing in 

 darkness. Its cells are e3ctremely turgid, with watery, soft, thin 

 walls,^ and acid cell-sap; its vascular bundles freely developed and 

 hardly lignified; and as before it is ill adapted to withstand the exigen- 

 ces of the ordinary environment." 



Thus obstructed transpiration in the forcing houses through feeble- 

 ness and short duration of light, and an atmosphere more humid than 

 the average in the open during the summer months favors watery 

 tissue, thin cell walls which are easily stretched and rapid growth in 

 size. The weakness of the cell walls is increased through lack of suffic- 

 ient building material, a result of the low degree of assimilation. 



During certain processes of destructive metabolism, brought about 

 by respiration, nitrogenous compounds like asparagin, leucin, etc., are 

 built up. When an abundance of carbohydrates are present in the 

 protoplasm the amides are worked up into more complex bodies. 



* Wollney, Beitnige zur Frage des Einfluss des Lichtes auf die Stoflf — und 

 Forni-buildung der Pflzen. Forsch. Agr. Bd. vii, 1884, pp. 351-375, cited in 

 Just's Bot. Johresbericht, 1884, i, pp. 30-31. 



t Ueber den Einfluss sonnigen oder Schattigen Standfortes auf die Ausbil- 

 dung der Laubblattes, Zeitchrift fiir Naturw. xvi, n. f. ix, 1, 2. Cited in Bot. 

 Zeitung, 1883, s 330, and Just's Bot Jahresbericht, 1883, ii, pp. 420-426. 



t Bot. Central!), 1884. No. 51, pp. 374-878. Just's Bot. Jahresb. 1884, i, p. 28. 



II On some Relations between Host and Parasite. Proceedings Royal Society, 

 Vol. 47, pp. 398-443. 



See also Vesque et Viet. Influence du Milieu sur les vegetaux, Ann. de Sci. 

 Nat. 6th Series, Bot. Vol. 12, 1881, p. 167. 



If Similar results have l)een obtained by students in Physiological Botany at 

 Cornell University. Bean plants grown with lessened degrees of dittused light 

 show corresponding grades of approach to etiolated plants and also corres- 

 ponding degrees of frail, succulent tissue. 



