728 EXPERIMENT STATION RECORD. 



By moderate treatment with acetic acid the taimin of the date was not ren- 

 dered entirely insohible, but the astringency disappeared in a few hours. The 

 intracellular luvertase passes into solution innnediately after the treatment, 

 and probably other catalytic agents are simultaneously released. 



The ripening pi'ocesses were found to be initiated not only by the acetic 

 acid, but also by other chemicals, such as acetic ether vapor, soaking for some 

 hours in a solution of potassium acetate, etc. 



Notes on the effect of mechanical pressure on the roots of Vicia faba, 

 Louise H. Gregory (Biil. Torrcij Bot. Club, 36 {1909), No. 8, pp. Jf57-J,62, flrjs. 

 .J). — studies are reported on the. effect of mechanical pressure on the roots of 

 V. faba, the object of the investigation being to determine the effect of pressure 

 on the mitotic figure, and also the morphological changes that take place in 

 compressed root cells. The investigation was carried on principally with roots 

 of V. faba, although those of maize and sunflower were also treated, with 

 rather poor results. 



In the different experiments the time of compi-ession and the amount of 

 pressure varied, and a number of morphological phenomena were noticed taking 

 place in the cells of the compressed roots. In all cases splits or rifts were 

 observed in some stage of formation in the different tissues. The beginnings 

 of these splits were found where there was the least pressure and continued 

 as the pressure was increased. The first indication of a definite split was the 

 appearance of cells which hati lost their entire contents, retaining, however, 

 their cell walls. In general the protoplasm of the cells had become vacuolated 

 and had shrunken from the wall, and in some cases the nuclei showed signs 

 of abnormality. 



In the second group of experiments, in which the pressure varied from 1,000 

 to 1,400 gm., the plerome cells were still more vacuolated and definite splits had 

 appeared not only in the external layer of plerome cells but also throughout 

 the central portion. In the third group of experiments, where the amount of 

 pressure was still greater, the plerome cells were broken up and the splits 

 were even more pronounced. 



It is concluded that although certain changes are produced by the compres- 

 sion, not even a maximum amount of pressure nor an absolute change in envi- 

 ronment would entii-ely stop or affect the normal development of the cells. 



The influence of traction on the formation of mechanical tissues in stems, 

 J. S. BoRDNER (Bot. Gaz., .',8 (1909), No. .',, pp. 2.5/-27.'/).— This is a detailed 

 report of investigations a preliminary account of which has already been given 

 (E. S. R., 21, p. 318). 



Light-perception organs of leaves, O. Damm (Naturtv. Rundscliau, 2-'f 

 (1909), Nos. 31^ pp. 389-391, figs. 5; 32, pp. 407-1,09).— A critical summary is 

 given of investigations by a number of authors relating to light perception on 

 the part of plants, the work being largely based upon that of Haberlandt. 



International catalogue of scientific literature. II — Bacteriology (Intcr- 

 vat. Cat. 8ci. Lit., 7 (1909), pp. T7//+77/).— A catalogue is given of the 

 litei-ature of bacteriology (including yeasts and molds) and parasitic proto- 

 zoology, over 6,000 titles being reported. 



FIELD CROPS. 



[Work with field crops at the Alaska stations], J. W. Gasser, J. W. Neal, 

 and C. W. H. Heideman (Alaska Stas. Rpt. 1908, pp. 33-1,1, .'/'/, Ii5-J,9. 52^}'). 

 pis. 3). — Brief notes are given on culture tests with numerous varieties of 

 grains, grasses, and potatoes at the Rampart, Fairbanks, and Copper Center 

 stations. 



