850 EXPERIMENT STATION RECORD. 



Heury^ Las published a bibliography and the conclusion of bis 

 investigations on tannin in wood begun in 1887. He studied 28 

 species and has located the tannin in the bark, sapwood, and inner 

 wood of the plant, and has shown the amounts present in each case. 



E. Mer^ has reviewed the question of the formation of duramen. In 

 the course of its development the duramen fixes the tannin which 

 impregnates the woody fibers of the older layers. The rannin gradu- 

 ally oxidizes and thus imparts to the duramen its ch.iracteristic reddish 

 brown tint. 



Gaston Bonnier-* made some experimental investigations on the sub- 

 ject of honeydew. The more common honeydew — that produced by 

 aphides and other insects— is levorotatovy. There is a honey of vege- 

 table origin which differs from that produced by insects in its method 

 of production, diurnal variation, and chemical comi^osition, and which 

 is very similar in character to the nectar of flowers. 



Other Avorks merely to be cited here are those of G. Clautriau ^ on 

 a chemical study of the glycogen in fungi and yeasts, and that of 

 Berthelot'' on arabinose. 



General cliemistry of ])lants. — The contributions to this subject have 

 been neither numerous nor important. Among the more important 

 might be mentioned the recent investigations of Berthelot and Andre *^ 

 relating to the decomposition of sugars under the influence of acids, 

 and especially upon the production of carbonic acid; and that of 

 Delepine" on the action of water on formic aldehyde, this substance 

 being considered one of the stages in the assimilation of carbon. 



E. rieurent" has established the analogies and the dift'erences between 

 the albuminoid products of animals and of plants. Gerber ^ has studied 

 the chemical phenomena of the maturing of fruits, especially the gas 

 exchanges between the acid fleshy fruits and the atmosphere during 

 processes of maturity. P6re^" has investigated the combustion of ter- 

 nary organic bodies. 



Analytical cliemistry. — In this class of investigations the determina- 

 tion of nitrogen is of especial interest. Pagnoul'^ has made a study 

 of the distribution of nitric nitrogen and ammoniacal nitrogen in the 

 ditt'ereut plant organs. Xitric nitrogen diminishes as one advances 

 toward the upx)er organs, while the total nitrogen increases. 



iBul. Soc. Bot. France, ser. 3, 3 (1896), p. 124. 



2Compt. Rend., 122 (1896), p. 91. 



3 Rev. g6n. Bot., 8 (1896), p. 5 (E. S. R., 7, p. 837). 



■• Bui. Soc. Bot. France, ser. 3, 3 (1896), p. 236. 



6 Compt. Rend., 123 (1896), p. 625. 



eConipt. Rend., 123 (1896), p. 567; Monitenr Qnesueville, 12 (1896), p. 907. 



■> Ibid., p. 120. 



8 Paris: Gautbier-Villars, 1896. 



9 Assoc. Fr. Av. Sci., Cougres de Carthage, 1896, p. 178. 



10 Ann. Inst. Pasteur, 10 (1896), p. 418. 

 " Ann. Agron., 22 (1896), pp. 540, 543. 



