AGEICULTURAL BOTANY. 729 



of the enzym content of the growing tissues. Although employing various 

 methods the authors were unable to find evidence to indicate the presence of 

 any of the commoner carbohydrases except cellulase. The commoner esterases 

 are likewise absent, but amidases are well represented. Urea, especially, is 

 rapidly transformed and urease is apparently widely distributed in the tissues. 

 Oxidases were not detected by any of the methods tested. 



Recent cytological studies on the formation of authocyanin pigments, A. 

 GuiLLiERMOND (Conipt. Roul. Acttd. Sci. [Paris], 151 {1013), No. 21, pp. 1000- 

 1002).— ThQ author, reporting on his more recent work (E. S. R., 29, p. 827), 

 states that anythocyanin and certain colorless compounds found there\v1th are 

 always dependent upon mitochondrial activity. It is thought that while these 

 coloring matters in general make their first appearance in the mitochondria as 

 pigments, they may be the result of a gradual transformation of the colorless 

 compounds above mentioned. 



Experimental production of anthocyanin identical with that in autumn 

 leaves, R. Co^fBES (Conipt. Rend. Acad. Sci. [Pans], 157 (1913), No. 21, pp. 

 1002-1005). — In a brief account given of a microchemical study of Ampelopsis 

 hcderacca, the author claims to have effected experimentally the alteration of 

 coloring matters found in the green leaf into a substance responding to tests 

 in the same manner as does the anthocyanin of red autumn leaves and therefore 

 held to be identical therewith. The change is held to be connected with a proc- 

 ess of reduction and not of oxidation (E. S. R., 23, p. 528). 



Transformation of anthocyanin pigment of red autumn leaves into the 

 yellow pigment proper to green leaves of the same plant, R. Combes (Conipt. 

 Rend. Acad. Sci. [Paris], 157 (1913), No. 25, pp. 145-'f-lJf57).— The author 

 claims to have induced experimentally in leaves of ivy the converse of the 

 change noted above in producing the yellow pigment from anthocyanin by a 

 process of oxidation thereof. It is maintained that the above facts require a 

 corresponding ch.ange from the views prevalent hitherto regarding the relations 

 of those pigments to oxygen. 



Growth stimulation by Roentgen rays of plant and animal tissues, E. 

 SciiwARz (Umschau, 18 (1914), No. 1, pp. 15, 16, figs. 2). — Besides brief notes 

 of some experiments with Roentgen rays on animal tissues, the author describes 

 briefly the effects of the rays on bean seedlings. Exposure for 30 seconds was 

 without marked influence and 300 seconds duration resulted in complete arrest 

 of development, but exposure for about IHO to 200 seconds gave vigorous growth. 



Variability in a vegetatively pure line of a hermaphroditic Mucor, A. F. 

 P.la;keslee (Ahs. in Science, n. ser., 39 (1914), No. 998, pp. 256, 257).— The 

 author states that separation cultures from a single spore sowing of the :Nrucor 

 gave a small percentage of colonies that differed sharply from the stock form. 

 The variations consisted in absence and increase or decrease of zygospore pro- 

 duction as well as peculiarity in color and growth. Some of these variants are 

 considered as only temporary conditions as they tend eventually to revert to the 

 normal type. Others are believed to be more permanent, but have not yet been 

 sulliciently investigated. All tend, at least in part, to reproduce the new char- 

 acters and some have maintained these for several generations. It is stated 

 that taxonomists would undoubtedly describe as distinct species these forms, 

 which would all be derived from a single .source. 



On physiological isolation in types of the genus Xanthium, C. A. Sriuix 

 (Ahs. in Science, n. scr., 39 (1914), No. 99S, p. 256).— .\ttention is called to 

 remarkable variations in the burs of what has been considered X. canadcnse 

 grown in this locality. Three distinct types were selected in the fall of 1912 

 and were grown together under identical conditions for breetling experiments. 



