328 Meyen's Report for 1839 on Physiological Botany. 



perature of the year being the same in the sixth degree of N. 

 lat and the thirty-first is remarkable, as showing the great 

 extent to which climate may be modified by locality. 



Robert Everest. 'I 



XLI. — Report of the Results of Researches in Physiological 

 Botany made in the year 1839. By F. J. Me yen, M.D., 

 Professor of Botany in the University of Berlin*. 



Observations on the presence of certain assimilated and secreted 

 substances in Plants, continued from p. 257. 



M. HuNEFELDf has with great diligence attempted to prove 

 the presence of amylum in the flowers of plants ; he found it 

 in the flowers of Calendula officinalis, in which plant it has 

 been already proved to exist by other chemists. M. Hiine- 

 feld then mentions thirty other plants in whose flowers he 

 discovered amylum with more or less distinctness; whether 

 however, he adds, the amylum of flowers always becomes blue 

 by iodine, he must still leave undetermined ; in the flowers of 

 Calendula it becomes blue, but in the others the colour was 

 more of a dark green. It appeared probable to M. Hiinefeld, 

 that it was the yellow colour of the flowers only which caused 

 this green tint ; but he has left this important point undeter- 

 mined, although it were easy to settle by a good microscope. 

 He contradicts himself in his statements, for globules in 

 the flowers which are not coloured blue by iodine cannot 

 be considered as amylum. Amylum, even that from mosses, 

 is always coloured blue ; and even when it becomes brown by 

 iodine, it is modified amylum. M. Hiinefeld mentions Tro- 

 pceolum majus as one of the few plants which contain amylum 

 in the stem ; this however is a tolerably common phenomenon. 

 Decoctions of the flowers of Calendula, Tropceolum, Helianthus, 

 &c. exhibited no trace of amylum, which is easily explained 

 by the microscopical examination of the parts thus treated ; 

 the amylum swells within the cells, but does not pass through 

 their walls. 



M. P. SaviJ of Pisa has published some observations on 

 the physical phenomenon seen in the leaves of Schinus Molle 



* Translated by Henry Croft, Esq., teacher of Chemistry in London. 



f Erdmann's and Marchand's Journal fur praktische Chemie, 1839, l er 

 band, p. 87—90. 



% Memorie Valdarncsi per cura del Dott. Corinaldi. Pisa, 1839, p. 42 — 

 48. 



