ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 63 



splitting-up of starch. The simplest of these is a substance with the 

 composition C 54 H 9G 4s , to which the author proposes to give the name 

 amylogen. He further suggests that the term dextrin should be limited 

 to the products of the hydrolysis of starch (except the sugars), those 

 which do not reduce Fehling's solution, and which are coloured indigo- 

 blue by iodine being amylo-dextrins. 



Formation of Starch in the Grain of Wheat. * — P. P. Deherain 

 and E. Dupont point out that the relative times at which the starch and 

 the proteids are formed differs in the case of wheat from what occurs 

 in the potato, tobacco, vine, &c. While in these plants reserves of 

 starch are formed in the leaves, this is never the case with wheat. It 

 would appear that the starch ultimately formed in the grains is not 

 transferred from the leaves, as is the case in the other plants men- 

 tioned, but is formed at a later period in the upper part of the stem. 



Distribution of the Acids in Plants. — M. Berthelot and G. Andre t 

 point out that the intensity of the acid reaction of the sap is not a 

 certain test for the amount of acids contained, the proportion of them 

 which exists in the form of saline (neutral) compounds being very 

 variable. The sap of plants has most commonly an acid reaction. 



According to A. Astruc, % the maximum amount of acid is always 

 found in the youngest part of the plant ; it is connected with the vigour 

 of growth and with the activity of cell-division. Thus the acidity of 

 the stem increases as the apex is approached. The leaves contain more 

 acid than the stem, and the largest amount is towards the zone of 

 growth. The acidity of the flower decreases from the bud condition up 

 to the period of complete expansion. 



Function of Calcium oxalate. § — A. Schneider discusses the pur- 

 pose of the crystals of calcium oxalate so widely distributed in plants, 

 and disputes the accepted theory that they are protective, since calcium 

 oxalate, being insoluble in water, has no taste, and is not poisonous. 

 The salt occurs in plants in four predominate types : — as crystal-sand 

 (root of Atropa Belladonna, stem-parenchyme of Solatium dulcamara, sp. 

 of Datura and Physalis, bark of Sambucus and Cinchona, &c.) ; in the 

 aggregate form ; in the prismatic form ; and as needle-shaped crystals 

 (raphides) ; the last especially in Monocotyledonous plants. The 

 author believes the function of calcium oxalate to be mainly that of 

 mechanical support ; while secondarily it plays the part of a reserve 

 product. This argument is supported by a reference to the parts of the 

 plant in which these crystals are most commonly found. 



Determination of the Presence of Cane-sugar in Plants. || — E. 

 Boui'quelot recommends, as a test for the presence of cane-sugar, the use 

 of the invertin of yeast, which decomposes cane-sugar (also gentianose 

 and raffinose, but these sugars arc rare in plants). This reagent has de- 

 termined the presence of cane-sugar in the substances tested, — rhizome 

 of Scrophularia nodosa, succulent pericarp of Cocos Yatai (25 grm. per 

 kgrm.), and horny endosperm of Asparagus officinalis (15 grm. per 



* Comptes Rendus, exxxiii. (1901) pp. 774-8. t Tom. cit., pp. 502-4. 



t Tom. cit., pp. 491-v?. § Bot. Gazette, xxxi. (1901) pp. 142-4. 



|| Comptes Rendus, exxxiii. (1901) pp. G90-2. 



