34-0 EXPERIMENT STATION RECORD. 



When growing plants were investigatefl the young ])art.s were affected pooner and 

 more severely than the more mature portions of the plant. The effect of varying 

 quantities of oxygen was not tested. 



The effect of sulphurous acid on plants, A. Wieler {Ber. De^it. Bat. Ge.tel.1., 20 

 {1902), x>. 55G; abs. in But. Cerdbl., iU {190.3), No. 10, p. ;?a5).— Sulphurous acid is 

 shown to have a more or less detrimental effect upon the assimilative activity of all 

 plant tissues. In the experiments of the author Ficn.s elaMica and Ahutilon sp. lost 

 all power of assimilation when subjected to atmospheres containing a considerable 

 quantity of the gas. The beech tree was found sensitive to 1 part in 814,000, and the 

 fir to 1 part in 500,000. Grapes were less injured by small (]uantities of suljthurous 

 fumes, and oaks were still more resistant. 



The author shows that the stomata are left open when exposed to the gas and the 

 carbon dioxid assimilating mesophyll is liable to injury. A somewhat prolonged 

 exposure to the gas causes the green tissues to become yellow and the chlorophyll 

 loses its ability to normally regenerate the destroyed chloroplasts. Another effect of 

 the sulphurous-acid gas is to drive the water from the leaf cells into the intercellular 

 spaces, as can be readily seen by the examination of such susceptible leaves as those 

 of the beech. 



The presence of hydrocyanic acid in the buds of Prunus, E. Verschaffelt 

 {Arch. Neerland. Sci. Exact, et Nat., 2. ser., 7 {1902), pp. 497-509; ahs. in Bat. Centhl., 

 92 {1903), No. 9, pp. 183, 184). — A report is given of studies made on the variation of 

 hydrocyanic acid during the opening of buds of species of Prunus. The proportion 

 of hydrocyanic acid in the buds and young shoots shows that the absolute quantity 

 increases very materially during the opening of the buds, while the relative quan- 

 tity in the different parts may remain the same. 



The cause of the variation is not positively determined, but it was found that the 

 hydrocyanic acid in the internodes was not less below closed buds than open ones. 

 In the case of Prunus laurocerasus the evergreen leaves placed in darkness retained 

 their hydrocyanic-acid content much longer than the recently developed leaves. 

 These begin to turn yellow and rapidly lose their prussic acid. There does not 

 appear to be any less hydrocyanic acid in the leaves after the liudding of branches 

 which carry them. It seems proliable that the buds and the young shoots contain 

 glucosids of the amygdalin type. 



The presence of solanin in tobacco seed, J. Starke {Rec. Inst. Bat. Univ. 

 BriLvelles, 5 {1902), pp. 295-298; ahs. in Bot. Centbl, 92 {1903), No. 9, pp. 182, 183).— 

 The author investigated the claim of Albo that tobacco seeds contain an alkaloid 

 similar to, if not identical with, solanin. The method employed was checked by 

 testing potato shoots for solanin, after which 12 gin. of tobacco seed and later 124 gm. 

 of the seed of Nicotiana macrophylla were tested in the same manner without finding 

 a trace of solanin or any analagous suljstance. 



The role of diffusion and osmotic pressure in plants, B. E. Livingston {Decen. 

 Pubs. Univ. Chicago, 2. ser., 8 {1903), pp. 162; abs. in Bot. Centbl, 93 {1903), No. 27, 

 p. 19). — In the first part of this work the author summarizes the physical side of 

 diffusion and osmotic pressure, while in the second portion he considers the physio- 

 logical problems involved. A summary is given on the effect of turgidity on plants, 

 and chapters are given on the al)sorption and transmission of water and materials 

 held in solution. In regard to the latter the author concludes that by far the most 

 important factor in their distribution through the plant bod}' is simple diffusion. 



Concerning the influence of osmotic pressure, the author concludes that while weak 

 solutions may accelerate vital activities, concentrated ones retard them. The effect 

 of high concentration seems to be due to the extraction of water from the living cells 

 of plants. Whether this is the direct cause of response to these concentrated solu- 

 tions is not known. 



The electro-motive force in plants, A. B. Plowman {Ainer. Jour. Sci., 4- ser., 15 

 {1903), pp. 94-104; a}>s. in Bot. Centbl., 93 {1903), No. 29, p. 61).— In a prelimiiaary 



