AGRICULTURAL BOTANY. 523 



of weight, varying from 1 to 4 per cent, the jimount of transpiration i>er unit 

 of time increased. Later when the loss in weight had increased from G to 10 

 per cent transpiration decreased. 



This Increase in the intensity of the transpiration is attributed to the dila- 

 tion of the openings of the stomata. The author states that the dilation Is 

 probably caused by the antagonism between the guard cells and the subsidiary 

 cells of the stomata, so that the turgor in the subsidiary cells begins to de- 

 crease sooner than in the guard cells, thus causing a stronger curvatui'e of the 

 guard cells and dilation of the slit of the stomata. 



Bark ringing and the descent of sap, J. M. Janse (Ann. Jard. Bot. Buiten- 

 zorg, 2. ser., 13 (1914), pt. 1, pp. 1-92, pis. 12). — K study has been made of the 

 effect of bark ringing on the descent of the elaborated material in trees, par- 

 ticular attention being paid to the force and direction of the current. The experi- 

 ments were made on horizontal branches so selected as to remove the force of 

 gravity, and the primary and final changes, the reversal of the direction of the 

 current, and the transi)ortation of nonnutrient materials were studied. 



In stems which were wounded by removing the bark in various ways, the 

 cambium layer and the wound tissue were found to influence the movement of 

 the elabortited material, and in addition to this, what the author calls a special 

 force, the exact nature of which was not determined, was always active. This 

 force is active in the secondary wood and assists in maintaining the current in 

 the same general direction of the elements in the surface of the wood. 



The destruction of paraffin by Bacillus prodigiosus and soil organisms, 

 R. Greig-Smith {Proc. Linn. Soc. N. 8. Wales, 39 {1914), pt. 3, pp. 538-541).— 

 Certain bacteria and molds having been shown capable of utilizing certain 

 hydrocarbons, the author has undertaken an experiment to determine whether 

 this action may not be taken by B. prodigiosus. Dried blood, casein, and finally 

 kieselguhr were coated with paraffin inoculated with B. prodigiosus and some 

 soil organisms, and it was found that in all cases the paraffin was decompose<l 

 to a considerable extent, the amount being uninfluenced by the nature of the 

 nitrogenous matter in the culture solution. 



The nitrate ferment and the formation of physiological species, ]M. W. 

 Beijerinck (K. Akad. Wetcnscli. A)iisterdam, Yersl. Wis en Xatiiiirk. Afdeel., 

 22 (1913-14), pt. 2, pp. 1163-1170; also in ditto, Proe. Sect. Set., 16 (1913-14), 

 pt. 2, pp. 1211-1211). — The author's studies have shown that the nitrate fer- 

 ment, growing at the expense of organic food, soon loses its power of oxidizing 

 nitrites to nitrates and changes into an apparently common saprophytic bac- 

 terium. 



Summarizing the results of his investigations, it is said that the nitrate fer- 

 ment reiiresents a definite physiological species which may be kept constant in 

 nearly pure inorganic nitrite solutions, but which, w'hen better nourished with 

 organic substances, passes Into another physiological species which is much 

 more constant. To the former the author gives the name 'SitrihaciUus oligo- 

 trophus. and to the latter N. pohjtrophus. The first is a nitrate-forming organ- 

 ism while the second is not. 



The study of plant enzyms, particularly with relation to oxidation, A. D. 

 Hall, E. F. Armstrong, et al. (Abs. in Rpt. Brit. Assoc. Adv. ScL, 1913, pp. 

 1 43-145). — This summarizes the second report of the committee on the study 

 of plant enzyms. and it lists related communications to the Royal Society, the 

 most recent noted being apparently that of Keeble, Armstrong, and Jones (E. S. 

 R., 30, p. 129). 



It is stated that during the past year progress has been made in elucidating 

 the part played by oxidizing catalysts in the production of plant jngments, Evi- 

 87235°— 15 3 



