1918] AGRICULTUEAL BOTANY. 729 



by the number of roots supplied with the nutrient. More detailed accounts of 

 these investigations have been published elsewhere (E. S. R., 36, pp. 546, 128, 

 431; 37, p. 222). 



Biometric studies on the somatic and genetic physiology of the sugar 

 heet, J. A. Haukis (Amer. Nat., 51 (Wn), No. 608, pp. 507-512).— Thin is a 

 discussion of the recent work by investigators bearing upon the conclusions 

 previously announced by the author with Gortner (E. S. R., 30, p. 208), re- 

 garding the correlations in the sugar beet, more particularly between the weight 

 of the root and the sugar content of the juice. 



Growth and imbitition, D. T. MacDougal and H. A. Spoehb {Pix>c. Amer. 

 Phil. Soc, 56 (1917), No. 4, pp. 289-352, figs. 13).— The chief purpose of the 

 studies here described was to correlate some of the more striking features of 

 the growth in plants with the action of the factors contributory thereto, and 

 to analyze this complex process so far as possible. 



To a study of cacti, continuing that previously reported (E. S. R., 36, p. 524), 

 was added a study chiefly of Zea and Triticum, results of which are given in 

 detail and discussed. Experimentation with colloids, presumably comparable 

 with protoplasm, has yielded many striking parallels with growth, making 

 possible some new correlations in metabolism, imbibition, and growth. Tiiere 

 has been effected, however, no simplification of the major processes of growth, 

 the advances being i-ather in the opposite direction. 



Newly determined features of carbohydrate metabolism have been found to be 

 extremely complex. Imbibition in the plant is not that of a single colloid and 

 swelling is not the simple resultant of the action of two or more substances. 

 The interaction between two emulsoids presents many possibilities. The pro- 

 teins viewed physiologically are thought to act as sensitizers to the carbohydrate 

 gels which make up the greater part of the bulk of the protoplast, and to pro- 

 duce in them highly specialized effects with acids, alkalis, and neutral solutions. 

 The general character of respiration and the nature and amount of its by- 

 products acting upon the sensitized protoplastic gel may be taken, it is thought, 

 to determine the general aspect, rate, course, and amount of growth in plants. 



Approximation of the limits of the germination in seeds of Lepidium 

 sativum, P. Lesage (Rev. Gen. Bat., 29 (1917), Nos. SJfO, pp. 97-112; 3J,1, pp. 

 137-158, fig. 1; 342, pp. 181-192). — The author reports with discussion some 

 tabulated results of experimentation which is still in progress on the germinabil- 

 Ity of seeds of L. sativum subjected for different periods of time to various 

 media, such as alcohol, ether, salt solutions, moist air, oxygen, and water. 



The physiological significance of tannin, J. Dekkek (Rec. Trav. Bot. N^er- 

 land., 14 (1917), No. 1, pp. 60, pis. 8).— The author describes a study of the 

 presence, location, and significance of tannin in Ribes, Rhododendron, Rosa, 

 and Kentia. This is conceded to be inadequate as a basis for sweeping general 

 conclusions, although these four plants agreed in showing the presence of tannin 

 in the conducting cells of the phloem. The agreement may be accidental or 

 of limited significance. 



A noteworthy result of this investigation is the discovery of tannin-conducting 

 channels in the pith and in the outer cortex of the younger shoots. These are 

 described. Differences are pointed out among the plants investigated. 



Large accumulations of tannin are noted in regions in which the life processes 

 are particularly active, as in the point of a shoot in full growth, in buds, or 

 near regions from which a stem or root arises. In such localities also a 

 considerable amount of calcium oxalate is often found. 



On the relation of chlorin to plant growth, W. E. Tottingham (Johns Hop- 

 kins Univ. Circ, n. ser., No. 3 (1917), pp. 217-221). — Preliminary investigations 

 are here discussed. 



