June, 1920] PHYSIOLOGY 425 



values decreased. The tumors which occur on inverted plants of Stilt's, fragffia at the b 

 of new branches are due to the fact that the root pole of I he cells of the new twig is in ju. 

 position t<> the root pole of the cells of the original plant. For normal growl h dissimilar poles 

 should meet. — William J. Itubbins. 



MOVEMENTS OF GROWTH AND TURGOR CHANGES 



2897. Stark, P. [Rev. of: Lundegardt. Ueber Beziehungen zwischen Reizgrosze und 

 Reaktion bei der geotropischen Bewegung und iiber den Autotropismus. (On the relation be- 

 tween the intensity of the stimulus and the reaction in geotropic movement, and on autotro- 

 pism.) Bot. Notiscr 1918:05-118. 1918.] Zcitschr. Allg. Physiol. Referate 19:27-29. 

 1919. — The reviewer points out salient features of the paper which may be summarized as 

 follows: (1) Bach and Pekelharing have shown that evident geotropism occurs when the 

 product of the intensity of the stimulus and the time reaches a certain constant value. 

 (2) According to Trondle the intensity (i) of the stimulus and the reaction time (T) can be 

 expressed by a mathematical formula, i(T — k) = ii(7\ — k). (3) Lundegardt finds that the 

 magnitude of the angle of rotation of a root is proportional to the presentation time and also 

 to the intensity of the stimulus. The proportion docs not hold for the longer presentation 

 times nor for the larger values of the intensity of the stimulus. If the amount of stimulus 

 (rm) is considered to be the product of the intensity and the presentation time, then the 

 greater the amount of stimulus the more rapidly (v) the angle of rotation reaches a certain 

 value. This can be expressed rm/riirii = v — h/vi — h, where h is a constant. — William J. 

 Robbins. 



GERMINATION, RENEWAL OF ACTIVITY 



2S9S. Charles, Mrs. M. E. S. Germination of wild cucumber. Amer. Bot. 25:66. 

 1919— See Bot. Absts. 3, Entry 2244. 



2899. Popp, M. [Rev. of: Urban, J., and E. Vitek. Untersuchungen iiber die Keim- 

 fahigkeit des Riibensamens. (The germination of beet seed.) Zeitschr. Zuckerindust. Boh- 

 men 40:295-300. 1916.] Biedermann's Zentralbl. Agrikulturchem. 47:267-269. 1918 — 

 From the account of the reviewer the chief results are as follows: (1) Influence of low tem- 

 perature on germination. Dry well-ripened beet seed were placed in liquid air ( — 1S0°C.) 

 and left for about one-half hour or until the liquid evaporated. They were then germinated 

 between blotters at a temperature of 20-30°C. The frozen seed were not injured by the low 

 temperature and 95 per cent of them germinated. Experiments were also conducted on 

 moist seed at low temperatures similar to the above and it was found that the seed germinated 

 poorly. If the beet seed at harvest are moist, the power of germination of the seed is con- 

 served by drying artificially. (2) Method of germinating. Germination on filter paper 

 gave far better results (1-13 per cent) than sand beds. — F. M. Schertz. 



2900. Russell, G. A. Effect of removing the pulp from camphor seed on germination 

 and the subsequent growth of the seedlings. Jour. Agric. Res. 17: 223-238. PI. 20-21. 1919. 

 — The usual method of planting the seed of the camphor tree without removing the pulp has 

 resulted in a very low per cent of germination. Russell has found that the removal of the 

 pulp before planting has resulted in hastening the germination by about two weeks and 

 increasing the germination about 525 per cent. Chiefly because of earlier germination, re- 

 moval of the pulp from the seed results in an increase in the number of seedlings of trans- 

 planting size by about 600 per cent. The resulting seedlings are also larger as shown by meas- 

 urements of stems, roots, and crowns. Seeds dried at 55°C. failed to germinate, as did also 

 those dried in an attic for several weeks. Seeds soaked in 5 per cent sulfuric acid after re- 

 moval of the pulp failed to germinate. Seeds fermented in a closed jar for 35 clays failed to 

 germinate. Freezing during three successive nights when the temperature fell to 20°F. re- 

 duced the germination by about 50 per cent. Soaking seeds in water for \ hour at 25° and 



