No. 1, November, 1921] PHYSIOLOGY 49 



in close contact. On October 12 the ovary, style, and stigma were practically complete, and 

 in this state the flower entered the winter, during which season no important changes took 

 place.—/. C. Th. Uphof. 



29G. West, C, G. E. Briggs, and F. Kidd. Methods and significant relations in the 

 quantitative analysis of plant growth New Phytol. 19: 200-207. 1920. — Suggestions are 

 offered for a method of quantitative analysis of plant growth week by week. For such an analy- 

 sis the primary data are "measurements of dry-weight and leaf area at intervals of a week or 

 less accompanied by measurements of respiration, assimilation, transpiration and chemical 

 analysis of the plant tissue, and continuous records of the various environmental factors 

 likely to affect growth." The significant secondary relations may be expressed through 4 

 series of niunbers, which can be put in the form of graphs, — relative growth rate, leaf area rates, 

 unit leaf rate, and relative leaf growth rate. Definitions and formulae are given for these. — 

 I. F. Lewis. 



MOVEMENTS OF GROWTH AND TURGOR CHANGES 



297. Bibb, L. B. Summation of dissimilar stimuli applied to leaflets of sensitive brier 

 (Schrankia). Jour. Gen. Physiol. 3 : 523-526. 1921. — In the morning the closure of 1 leaflet of 

 Schrankia uncinata Willd. does not result in the closure of the next distal leaflet, while in the 

 afternoon such closure will inaugurate a wave of closures of the distal leaflets in turn. It 

 was found that, at a time of day when the closure of 1 leaflet would not normally cause the 

 closure of the others, an exposure of the pinnae to chlorine or ammonia gas would so sensitize 

 them that all of the leaflets would close in turn when 1 was touched. This is taken as a demon- 

 stration of the summation of dissimilar stimuli. — Otis F. Curtis. 



298. Small, J. Preliminary note on a hydrion differentiation theory of heliotropism. 

 New Phytol. 19 : 275-276. 1920. — The possibility is suggested that the direction of heliotropio 

 curvatures is governed by the hydrion concentration of the continuous phase of the plasma 

 membranes of the perceptive cells. — I. F. Lewis. 



299. Small, J. Preliminary notes on additional evidence for the hydrion differentiation 

 theory of geotropism. III. A theory of the origin of leaves. New Phytol. 19: 210-212. Fig. 

 1-S. 1920. — Analogies are suggested between the zones of potential differences in the stem 

 and its lateral organs and the lines of force of certain magnetic fields. — I. F. Lewis. 



300. Small, J., and M, W. Lea. Preliminary notes on additional evidence for the hydrion 

 differentiation theory of geotropism. I. On the reversal of geotropic curvature in the stem. 

 New Phytol. 19: 208-209. 1920. — In most cases, when shoots of different plants are coated 

 with vaseline and placed horizontally in the dark, they curve downward. The reversal of 

 the geotropic response is due to the accumulation of CO2 within the tissues. — /. F. Lewis. 



301. Small, J., and M. J. Ltnn. Preliminary notes on additional evidence for the 

 hydrion differentiation theory of geotropism. II. On the angle of balance in roots, stems and 

 leaves. New Phytol. 19: 209-210. 1920. — Announcement is made that the angle at the junc- 

 tion of a lateral organ (root, stem, or leaf) with the main axis varies directly with the length 

 of the lateral, (L), and inversely as the distance to the tip of the main axis, (D). The fraction 

 ^ varies as the sine of the angle. — I. F. Lewis. 



REGENERATION, CORRELATION 



302. Child, C. M. Certain aspects of the problem of physiological correlation. Amer, 

 Jour. Bot. 8: 286-295. 1921. — The author describes briefly the existence in animals of physio- 

 logical or metabolic gradients from a dominant apical region to a subordinate basal one and 

 shows that the localization and differentiation of organs and parts occur in a definite relation 

 to this gradient and are determined by it. The range of dominance of the apical region of 

 such a gradient is usually limited, and regions beyond this range become physiologically 



