230 EXPERIMENT STATION EECOED. 



of the cowpea (E. S. B., 19, p. 231; 26, p. 635) based upon new data bearing 

 ou the habitat and the botanical characteristics of Vigna found in Africa, which 

 seems to bring Vigna sinensis, V. catjang, and V. sesquipedalis into one and the 

 same species. The author concludes that tJie wild African plant, Y. sinensis, 

 with blacldsh scabrous pods and scabrous leaflets is the original wild form of 

 our cultivated cowpea. 



A comparison of the Mam.moth and Spanish peanuts as grown in central 

 Iowa, H. W. Clark (Science, n. ser., 36 {1912), No. 928, pp. ^SS-J/DO) .—A strain 

 of a Virginia peanut, known as Mammoth, was planted on May 8 in comparison 

 with a small prolific Spanish peanut. Similar treatment was given throughout 

 the season, and both were harvested on October 23, the date of the first killing 

 frost Tabulated measurements of the nuts and kernels of both vr-rieties are 

 given. The Mammoth peanut gave a little more than 68 iX!r cent larger yield 

 of kernels. 



Gt)od seed potatoes and how to produce them, W. Stuart ( U. S. Dept. 

 Agr., Farmers' Bui. 533. pp. 16, figs. S). — The author discusses the production of 

 the potato in the United States since 1868, and describes methods of selecting 

 good seed tubers, including the tuber-unit method, previously de.scribed ( E. S. R., 

 28, p. 835) . It is suggested that high-grade seed would increase the return of the 

 potato crop of the country by many million dollars, and that all seed should be 

 treated with formalin solution. 



Changes in Irish potatoes during storage, C. O. Appleman (Maryland 8ta. 

 Bui. 167, pp. 327-33 Jf). — This bulletin gives results of investigations to deter- 

 mine the " relation of temperature to starch and sugar transformations; changes 

 due to respiration and its dependence upon external and Internal factors; causes 

 of loss in weight ; and effects of sprouting." Data are arranged in tabular form. 



It was found that " sugar accumulates in potatoes at the expense of the 

 starch when the temperature falls to 38° F, The rate of accumulation is most 

 rapid between 32 and 29°. Potatoes exposed to the above temperatures for onlj' 

 a few days will show a very slight sugar accumulation. A long exposure is 

 necessary before the accumulation becomes significant. The maximum of from 

 3 to 4 per cent is reached in from 4 to 6 weeks. Freezing does not begin until 

 the temperature is between 28 and 26°. If potatoes, which have become sweet 

 through long exposure to low temperature, are brought into a room of 70 to 75° 

 for a week, about four-fifths of the accumulated sugar will be converted back 

 into starch; the remaining fifth wIU be lost through respiration. A longer 

 exposure of 3 or 4 weeks in the cellar or vault after the temperature has risen 

 to 45 or 50° will remove most of the accumulated sugar. 



" Respiration converts starch and sugar into water and carbon dioxid. This 

 process is continually going on in stored potatoes. The rate of respiration is 

 influenced most by temperature. It increases as the temperature rises within 

 certain limits and gradually decreases as the temperature falls, becoming very 

 weak just above the freezing point. The rate of respiration is also accelerated 

 by accumulated sugar, germinating buds, moisture, and light. . . . The heating 

 of potatoes in large heaps or bins is due to high respiration and poor ventila- 

 tion. . . . 



" Potatoes lose in weight during storage, due to evaporated water and respired 

 carbon dioxid- Warm, dry conditions favor evaporation. Loss by carbon 

 dioxid is greatest at high temperatures. Under similar conditions loss in weight 

 is much greater right after digging than during the winter months. The rate 

 of loss increases again with sprouting and warm weather. Starch, sugar, and 

 proteins are rapidly depleted in sprouting potatoes. The minimum sprouting at 

 the end of the rest period wiU occur under cold, dry condition. Removing the 

 sprouts repeatedly docs not seem to weaken the buds for seed. ... A storage 



