FIELD CROPS. 533 



tlio jioruiination tests, and the care of seed corn are discussed in a ixipular 

 manner. 



The culture of cotton without irrigation, (i. Pretrel (Bii}. >s'of'. Horf. ct 

 Avicnlt. Tunimc, 7 (WOS), A'o. 31, pp. !)l-9.j). — Experiments in growing cotton 

 without irrigation were made in 1!)0T in the vicinity of Tunis. Tlie results sliow 

 that a good tiber, although not quite as valuable as Egyptian and American 

 cotton grown with irrigation, can be produced in that locality under those condi- 

 tions. In one of the fields in which this work was conducted, and where 

 weather conditions did not interfere with the expeinment, a yield of 7.81 Ivg. 

 (about 17 lbs.) of fiber was harvested from 322 plants. It was also observed 

 tliat the tap root of the plants was in most cases quite straight and long, having 

 gone down deep into the soil for the purpose of finding the necessary moisture. 



The flax stem, T. TAivrJiES {Islatuurlc. Verhanclel. Holland. Maatsch. Wcicnscli. 

 Haarlem, 3. scr., 6 {1901), Xo. .'/, pp. ^'II+2S5, pis. 6). — This publication is a 

 monograph on statistics and the anatomy of flax. The following subjects are 

 treated: The origin and history of cultivated flax, the variation and correlation 

 of macroscopic characters, the influence of soil and space on flax plants, the 

 development and structure of the stem, and the fiber. An extensive bibliog- 

 raphy on flax and its culture is included. 



Trials of hemp, H. L. Bolley {North Dakota Sta. Rpt. 1907, pt. 1, pp. SI, 

 82). — Comparative tests were made with hemp seed secured from Russia, Man- 

 churia, and Kentucky. The Russian hemp did not prove very satisfactory. The 

 Kentucky seed produced hemp straw S or 12 ft. high, of good quality and 

 mature, but the seed did not ripen before frost. It is believed, however, that 

 by planting the crop earlier mature seed can be grown in that region. The 

 Manchurian hemp when planted for seed purposes matured thoroughly, but in 

 quality of fiber it ranked behind the Kentucky type. 



Hop culture and handling-, C. Fruwirth {Hopfenbau und Hopfoihchandlung. 

 Berlin, 1908, pp. riII-\-185, figs. 5.9).— This book treats of the structure and the 

 life of the hop plant, the culture of the crop, hops as a commercial article, and 

 the methods of promoting hop culture and connnerce. 



A study of the factors influencing the improvement of the potato, E. M. 

 East {Illinois Sta. Bui. 127, pp. 37o--'i56, figs. 10). — This bulletin discusses the 

 use of species of Solanum other than the potato, cites descriptions of the 

 original plant from the earlier writers on the subject, describes the modern 

 plant, outlines methods of breeding, considers at some length the inheritance 

 of characters in tuber selection, and more briefly the hypothesis of degeneration, 

 discontinuous variations, and graft-hybrids, and reports results secured in 

 experiments on the improvement of the tuber in quality. In the treatment of 

 the difterent subjects the work of a large number of investigators is reviewed, 

 and the bulletin concludes with a bibliography of 114 references. 



The author found a great difference in varieties regarding the value of 

 luxui'iant vegetation as a guide in selecting high-yielding plants. Large vines 

 as comjiared with medium vines gave fair results in most cases, but in some 

 varieties, as Manistee, large vines rather indicated that excessive vegetative 

 growth was opposed to maximum yields of tubers. No constant difference was 

 found due to selection of plants with a single stem and those branching just 

 Im'Iow or just above the ground, providing other conditions were equal. There 

 is apparently an optimum shade of color in vines constant with the variety and 

 correlative with or a result of vigor in the plant. Light-colored vines gave 

 fewer potatoes although of good size, while darker-colored vines either gave no 

 set of tubers or a large set of very small ones, 



