1917] AGRlCtTLTURAL BOTANY. 127 



also reaches a maximum. Both of these then fall rapidly to a minimum of 

 about 0.2 per cent just after midnight, the starch apparently changing directly 

 to dextrose, which shows a corresponding increase in the leaf. 



In the stalks, reducing sugars predominate greatly over saccharose. As in 

 the case of the mangold, it is probable that cane sugar is the first sugar 

 formed in the leaf and that it is hydrolyzed by invertase in the veins, mid- 

 ribs, and stalks for the purpose of translocation. As in the mangold, the 

 determination of the true proportions of dextrose and levulose is prevented 

 by the presence of soluble, optically active substances. 



Maltose is invariably absent from the leaf of the potato plant and the 

 leaves of other plants which form much starch in the leaf. The degradation 

 of starch in the leaves is thought to be effected by a mixture of euzyms simi- 

 lar to the enzyms of Aspergillus orysw. Maltose is always present in relative 

 excess so that starch is degraded completely to dextrose, the series of changes 

 being starch,— » dextrins,—» maltose,— > dextrose. 



Physiological observations on alkaloids, latex, and oxidases in Papaver 

 somniferum, R. H. True and W. W. Stockbekgek (Amcr. Jour. Bot., 3 (1916), 

 No. 1, pp. 1-11). — Presenting the results of work done during 1902 to 190.5, 

 but afterwards interrupted, the authors state that in the case of P. somni- 

 ferum the oxidase reaction is most active in the upper parts of the plant, 

 especially in the floral structures, capsules, and actively growing parts. In 

 this respect it parallels the distribution of the latex, which in itself is most 

 active. The peroxidase reaction shows less variation in intensity in the dif- 

 ferent regions. Oxidase seems to be inactivated during the course of its 

 action, as has been notetl also in case of Irish potato. This appears to indicate 

 that the oxidase reaction is not caused by a catalyzing agent. Intensity of 

 oxidase reaction roughly paralleled the alkaloid content except in the root, where 

 the latter was relatively the higher. Alkaloids seem not to exist as such in 

 the poppy, but to appear as products of the oxidase action on the constituents 

 present in the latex reacting in the presence of oxygen. Alkaloids of Atropa 

 belladonna differ from those of the poppy in that thoy are found in structures 

 dried out of contact with free oxygen and appear to exist ready formed in the 

 plant. 



A substance coag'ulating inulin and accompanying it in vegetable tissues, 

 J. Wolff (Cotnpt. Rend. Acad. Sci. [Paris], 162 {1916), No. U, pp. 514-516).— 

 The author claims to have found in roots of Cichorium intybus and in tuber- 

 cles of Dahlia variabilis a substance which coagulates very actively the juices 

 extracted from these plants and precipitates inulin from the solutions. For 

 this agent the name inulo-coagulase is proposed. After 1 hour of coagulation, 

 the precipitated inulin represented 35 per cent, and after 18 hours 75 per 

 cent of the total quantity. 



The constitution of anthocyanins, R. Willstatteb [Ber. Detif. Pharm. 

 GeselL, 25 (1915), No. 8, pp. Ii38-U9 ; abs. in Rev. G&n. Sei., 27 (1916), No. 7, 

 p. 199). — Summarizing in this address the results of work recently done by 

 himself and his collaborators, the author states that of about 20 anthocyanins 

 thus far studied, 6 were obtained from fruits, the rest from flowers. The 

 anthocyanins appertain to the oxonium salts. In all cases, these substances 

 were found as glucosids and, by treatment, gave for each case a sugar and a 

 coloring matter. These coloring matters have been termed anthocyanidins. 

 Several are designated as to their origin and are discussed. Chemically, they 

 are said to resemble closely the anthocyanins, which are widely distributed in 

 nature. 



