826 EXPEEIMENT STATION EECORD. 



It was found that under constant storage temperature starch was depleted 

 while the reducing sugars showed a slight increase, the carbohydrate changes 

 being more rapid in the stem end of the tubers. Both diastase and invertase 

 activity was doubled, the increase being greater in the stem half of the potato. 

 Catalase showed a marked Increase, which was slightly greater in the juice 

 from the seed end. The nitrogen of monamino acids and their amid derivatives 

 increased, while that of the diamino acids and other organic bases and the 

 water insoluble protein nitrogen decreased. The abundant water soluble pro- 

 tein nitrogen in the tubers showed a very slight increase during sprouting. 

 Organic extractive and lipoid phosphorus increased at the expense of protein 

 and inorganic phosphorus. The increase in lipoid phosphorus began earlier and 

 increased more rapidly in the seed end. The decrease in inorganic phosphorus 

 occurred in the seed end only. In many cases the metabolic activity was found 

 greater in the stem half, although th.e sprouts were all borne on the seed end 

 of the tuber. 



Differential permeability, W. J. V. Osterhout (Ahs. in Science, n. ser., 

 39 {Wl.'i), No. 999, p. 293). — ^Attention is called to the differences in perme- 

 ability possessed by various kiixls of surfaces in the cell, such as the plasma 

 membrane, the vacuole-wall, the nuclear wall, the surface of the chromatophore, 

 and the cell wall. The author suggests the term differential permeability as an 

 appropriate designation of these phenomena. 



Inefficacy of cultivation for destroying weed seeds, O. Munerati {Atti R. 

 Accad. Lined, Rend. CI. Sei. Fis., Mat. e Nat., 5. ser., 22 {1913), I, No. 2, pp. 

 120-126; aJ)S. in Internat. Inst. Agr. [Rome'[, Mo. Bui. Agr. Intel, and Plant 

 Diseases, 4 {1913), No. 4, pp. 661, 662). — The author concludes a briefer ac- 

 count of recent work (E. S. R., 30, p. 332) by stating in substance that the age 

 of weed seeds has usually much more to do with the time and percentage of 

 germination than do such conditions as moisture and depth below the surface; 

 that slow germinability favors persistence of weeds ; that superficial or frequent 

 working of the soil does not necessarily destroy many weed seeds; and that the 

 only method that is certainly efficacious in checking propagation of harmful 

 weeds is their destruction before the seeds ripen and fall to the ground. 



Recent contributions on problems regarding mycorrhiza, J. Peklo {Ztschr. 

 Gdrungs Physiol., 2 {1913), No. 4, pp. 246-2S9; ahs. in Ztschr. Bot., 6 {1914), 

 No. 3, pp. 293-295). — This is a detailed account of recent studies by the author 

 and others on the cytology and physiology of fungal mycorrhiza in nutritive 

 relation with pine and fir, more particularly as regards the assimilation of 

 atmospheric nitrogen, which some are claimed to be able to accomplish. 



The counting of protozoa in soil, J. Killer {Centhl. Bakt. [etc.], 2. Ait., 

 37 {1913), No. 17-21, pp. 521-524) .—The author discusses methods of counting 

 soil protozoa, emphasizing the proper procedure and precautionary measures 

 for obtaining accurate results. 



Tests of different concentrations of seven different nutritive solutions inocu- 

 lated with different soil solutions showed that the chemical composition of 

 the culture medium and the concentration of the nutritive solutions exerted a 

 marked influence on the kind and powers of development of the soil protozoa. 

 It is concluded that the values of all counting methods are limited and that 

 a knowledge of the effect, intensity, and nature of the activity of the soil 

 protozoa is much more important. 



Studies of teratological phenomena in their relation to evolution and the 

 problems of heredity. — I, A study of certain floral abnormalities in Nico- 

 tiana and its bearing on theories of dominance, O. E. White {Amer. Jour. 

 Bot., 1 {19U), No. 1, pp. 23-36, figs. 4; ahs. in Science, n. ser., 39 {1914), No. 

 998, p. 2oo). — Studies are reported of races of Nicotiana showing petalody. 



