252 Progress of Phytochemistry in 1835. 



M. Lassaigne* found uncrystallized sugar not only in the 

 ])lants already known to contain it, but also 1 per cent, in the 

 leaves of Moms alba, M. Zenneck found nearly 6 per cent.f 

 in the fruit of Panicum miliaceum, and M. SemmolaJ found 

 12*5 per cent, of crystalline sugar in the radical tubers of Q/- 

 petiis esculenius, M. Malagutti§ has given a very good paper 

 on_sugar, from which we may remark that cane sugar is hy- 

 drated, i, e. changed into grape sugar, by all weak acids with- 

 out exception. The latter has been found in all acid fruits; 

 from this the process necessary to its origin becomes evident. 

 If the action of the acids on the grape sugar continues, water 

 is again taken from it, and ulmic acid is formed. If at the 

 same time the atmospheric air acts on it, oxidation takes place, 

 and by this the formation of formic acid. 



The crystalline part of manna, mannite, was found by M. 

 Winckler in a preparation from the buds of the poplar ||, and 

 according to Boutron-Charlard and Guillemette^, thegrena- 

 din found in the bark of the roots of Punica Granatum is also 

 mannite. Grenadin acquires from this circumstance more 

 importance, and deserves a closer examination as to its occur- 

 rence. 



We here again direct attention to the rather too much neg- 

 lected experiments of MM. Fourcroy and Vauquelin on the 

 sap o{ Allium Cepa, and of Laugier** on the sap of Daucus Ca-- 

 rota. All three chemists found in the saps of those plants, 

 after they had begun to ferment, crystalline manna, which they 

 were not able to extract from the fresh saps. At the same 

 time the fermented saps indicate free acids, and, according to 

 Laugier, the manna from Fraxinus has in its fresh state a smell 

 of acid. Perhaps the natural or artificial process of originating 

 mannite might be a task worthy of chemical research. 



M. Buchner, jun.f f examined the sap of the nectaries of 

 Agave geminiflora^ which flowered in autumn, 1834, in the 

 Botanical Garden of Munich. It possessed the consistence of 

 a thin syrup, specific gravity = 1*09, and contained a great 

 quantity of uncrystalline sugar, water, and traces of gypsum. 

 The sweetish putrid smell disappeared when in contact with 

 die air. M. Buchner, sen.^ examined some time back the 

 sap of the nectaries of Agave americana^ and Anthon that of 

 A, IkridOf which exhibited nearly the same qualities. 

 [To be continued.] 



♦ JourtL. de Chim. Med., 1834. f Buchn. Repert. yVo\. xlix. 



+ Joum. dc Chim. Med., 1834, p. 676. § Journ. de Pharvi. Sept. 1835. 

 II Buchn. Repert.y\o\. li. part 1. ^ Journ. dc Fharm.y April 1835. 



#• Mem. du Mus. d^Hist. Nat., vol. iv. page 102—108. 

 tt Buchn. Reperi., vol. li. 



