234 forestry Quarterly. 



does. Yet the total of sugar and fat is not enough to account for 

 all the starch dissolved. 



]\Ier/ writing in the same year as Fischer and in a subsequent 

 paper in 1898, differed from Fischer by denying that glucose was 

 one of the transformed products of starch. 



D'Arbaumont- examined the stems of nearly 100 species of 

 trees and shrubs, and came to the conclusion that the disappear- 

 ance of starch in winter, though influenced by the temperature 

 environment, is a fixed habit in woody plants, inasmuch as several 

 trees, kept in a warm plant house over winter, nevertheless lost 

 all their starch from the stem. D'Arbaumont's observations do 

 not seem to coincide with Fischer's as to the greater diminution 

 of starch in soft-wood trees compared with hard-woods, inas- 

 much as both hard-woods and soft-woods are found in his list 

 the members of which lost all their stem starch in winter, and 

 both hard-woods and soft-woods are found in his list the mem- 

 bers of which retain some starch in the stem in winter. 



To the questions under discussion, Sablon^ made the next im- 

 portant contribution. His methods are mostly microscopical, by 

 chemical analysis. Fischer had suggested that the starch, on 

 dissolving in early winter, passed in part into an unknown sub- 

 stance. This substance Sablon claimed to have discovered in 

 reserve cellulose. Moreover, according to his analyses, reserve 

 cellulose constitutes by far the largest part of the non-nitrogenous 

 reserves, starch, sugar and fat being wholly subordinate. In 

 the stem of the chestnut, for instance, in proportion to the dry 

 weight of the stem, the maximum content of starch was, accord- 

 ing to Sablon, 4.6%, minimum 2.4% ; the maximum of sugar 

 was 4.3%, minimum 2.1%; the maximum of fat 1.1%, minimum 

 0.6% ; while the maximum of reserve cellulose was 20.2%, 

 minimum 14.4%. The presence of reserve cellulose was deter- 

 mined not only by extracting the finely ground powder with 

 boiling 10% hydrochloric acid, and subsequent chemical analysis, 

 but by the use of the microscope, the xylem cells showing in 

 winter a layer of cellulose which disappeared in spring. Some 



'Des Variations qu' eprouve la Reserve amylacee des Arbres aux di- 

 verses Epoques de I' Annee. Bull. Soc. Bot. France, XLV, 1898, 299. 



^Sur r Evolution de la Chlorophylle et de 1' Amidon dans le Tige. 

 Ann. Sci. Nat. 8 ser. T. 13, 1901, 319; T. 14, 125. 



'Recherches physiologiques sur les Matieres de Reserves des Arbres. 

 Rev. gen. Bot. XVI, 1904, 401. 



