AGRICULTURAL BOTANY. 729 



the water columns of the plaut. At any rate, this rupture represents, apparently, 

 a rather definite critical point in the course of water extraction by the plant, 

 probably the same as that about which the concept of permanent wilting has 

 developed. This plant appears to have reached the stage of permanent wilting 

 in about five hours. 



A new method of continuous automatic registration, of transpiration, R. A. 

 Robertson and S. J. Wilkie {Trans, and Proc. Bot. Soc. Edinb., 26 (1914-15), 

 pt. 4, P- 4^2, pi. 1). — A comparatively simple apparatus is described by means of 

 which the vapor transpired by a plaut can be automatically trapped and 

 weighed and a practically continuous record of the weight made on a revolving 

 drum, the interruptions being so infrequent as not to detract materially from 

 the value of the experiment. 



The air is drawn through calcium chlorid tubes to the receiver containing the 

 plant, and then out through a chlorid tube suspended from an arm of a deli- 

 cately poised lever, to the other end of which is attached a tracing pencil re- 

 cording on the revolving drum the depression of the other end. The chlorid is 

 renewed once a day, the tubing is very flexible, and condensation on the glass 

 cover of the receiver is obviated by the regulation of the rate of aspiration 

 and by keeping the temperature constant. 



Satisfactory continuous records extending over 12 to 30 days are said to 

 have been made for herbaceous plants, succulents, and needle-leaved gymno- 

 sperms without appreciably damaging the experimental material. 



Observations on the osazone method of locating sugars in plant tissues, 

 S. Mangham (Ann. Bot. [Lmulon'i, 29 {.1915), No. 115, lip. 369-391, pi. i).— The 

 author has extended the studies previously noted (E. S. R., 26, p. 229), and it 

 is stated that additional light has been thrown on the value of the method 

 employed (which is herein presented in greater detail) and on the limits of its 

 application. 



Among the results detailed, it is stated that on the whole the presence of 

 osazone may be held to indicate with a fair degree of accuracy the distribution 

 of the reacting sugars before treatment with the reagent. The presence of 

 impurities in the form of various cell contents, particulax'ly colloidal substances, 

 is thought to influence the crystallization of osazone, and may account for some 

 irregularity in its behavior in plant tissues. It is thought advisable, when 

 using Senft's reagent, to reexamine the preparations from time to time over a 

 period of at least four months before attempting to draw conclusions 

 therefrom. 



A bibliogi-aphy is given. 



Migration of reserve material to the seed in barley considered as a factor 

 of productivity, E. S. Beaven {Abs. in Rpt. Brit. Assoc. Adv. ScL, 84 {1914), 

 pp. 660, 661). — This is an abstract of a paper reporting and discussing the work 

 of the author in collaboration with Biffin and Gosset. It gives a summary of 

 the conclusions arrived at from the studies of the last five years, more par- 

 ticularly as to the value for selection purposes of the accurate determination 

 of the relative seed-forming energy as shown by the coefficient of migration of 

 different races of barley. 



It is considered to be impracticable, during the initiatory stages of new 

 races, to separate with any high degree of certainty the most productive races 

 from among those originated by artificial crossing by employment of the merely 

 empirical methods hitherto employed. 



The distribution of nitrogen in the seeds of Acacia pycnantha, J. M. 

 Petrie and H. G. Chapman {Abs. in Rpt. Brit. Assoc. Adv. HcL, 84 (1914), PP- 

 666, 667). — In this summary of work by the authors, it is stated that the whole 



