30 HORTICULTURE [BoT. Absts., Vol. X, 



151. Allen, W. J. The pruning of Rome Beauty. Agric. Gaz. New South Wales 32: 

 429-434. 10 fig. 1921. 



152. Bakke, a. L., W. a. Radspinnek, and T. J. Maney. A new factor in the determina- 

 tion of the hardiness of the apple. Proc. Amer. See. Hort. Sci.l7: 279-289. 1920 [1921].— 

 The investigators used the current season's wood growth of IS varieties of apples, 15 years old, 

 and wood from varieties of nursery trees 2 years old. Samples were collected during the dor- 

 mant season, when the buds were swelling, at blossoming time, during summer growth, and 

 at the wood-ripening period. Tests were made on each for the depression of the freezing 

 point, water content, ash content, and hydrogen-ion concentration. Since the hydrogen- 

 ion concentration proved to be the same throughout, it was dropped from consideration. 

 Tables are given for each period and include the date of collecting, variety, freezing point 

 lowering, per cent of moisture, and the hardiness factor. In separating the varieties into 

 groups of 4 according to recognized hardiness the per cent of ash generally increases as hardi- 

 ness decreases, which appears to be of some significance. During the period at which buds 

 are swelling the lowering of the freezing point is least. The authors state "the results ob- 

 tained point out the possibility of using the depression of the freezing point and the moisture 

 content as an index in ascertaining comparative hardiness. The solutes which are responsible 

 for differences in the ash appear to be significant in the general question of hardiness." It is 

 thought that measurements and tests to determine the hardiness should be made at a time 

 when the metabolic processes of the plant are at their maximum. — H. W. Richey. 



153. Chasset, L. Eborgnage d'hiver des yeux du poirier. [Winter disbudding of pear 

 trees.] Rev. Hort. 93 : 263-264. 1921. — If branches are cut back in winter, 2 strong branches 

 almost certainly will develop immediately below the cut, and the buds remaining below them 

 are starved. By carefully judging the amount of heading according to the vigor of the variety 

 and age of the tree, and then removing the 2 buds immediately below the topmost one, the 

 remaining buds are nourished to better advantage, and the development of fruit buds and 

 fruit spurs is likely to follow. — E. J . Kraus. 



154. Chasset, L. Quelques bonnes cerises & cultiver. [Some good cherries worth grow- 

 ing.] Rev. Hort. 93: 274-275. 1921. — A list is given of several varieties, suitable for various 

 regions. — E. J. Kraus. 



155. Cooper, J. R. Commercial grape growing. Arkansas Agric. Exp. Sta. Bull. 174. 

 ItO p., 16 pi. 1921. — The author presents a general bulletin giving recommendations for the 

 selection of varieties for Arkansas, directions for preparation of the soil, planting, trellising, 

 and pruning. Fruiting habits and systems of training are described and illustrated. Methods 

 of cultivation, cover-cropping, and fertilizing suited to Arkansas conditions, are given. A 

 discussion of pests includes brief descriptions of some of the insect pests and diseases, with 

 general control measures, a spray schedule, and a discussion of spray materials used. — 

 D. Reddick. 



156. Enfer, V. Les incisions sur les branches charpentiers du poirier. [Incisions on the 

 scaffold branches of the pear.] Rev. Hort. 93: 250-251. 1921. — Specific directions are given 

 on making incisions in the vicinity of several types of branches in order to direct the character 

 of the growth of the branches, behavior, and fruit-bud production. — E. J . Kraus. 



157. H., T. A. Cocoa and chocolate. [Rev. of : Knapp, A. W. Cocoa and chocolate: their 

 history from plantation to consumer, xii + 210 p. Chapman and Hall: London, 1920.] 

 Nature 107: 357. 1921. 



158. Jahandiez, E. La grande gelee des 17 et 18 decembre 1920 sur le littoral medi- 

 terraneen. [The great freeze of December 17 and 18, 1920, on the Mediterranean coast.] Rev. 

 Hort. 93: 266-267. 1921. — Notes are given on the extent of the damage to many species of 

 plants caused by temperatures ranging to as low as — 13°C. in various sections. — E. J. Kraus. 



