244 ANNUAL OF SCIENTIFIC DISCOVERY. 



CONSTITUTION OF FHUITS. 



Fresenius (in Liebig's Annalen) gives the following table of the proportion 

 of malic acid (i.), sugar (n.)j and pectin or gum (in.) contained in the com- 

 mon domestic fruits : 



i. n. in. 



Peaches 67 1-57 3-78 



Apricots, 1-09 1-80 5~S2 



Plums, 1-30 2-12 2-41 



Reiue Claudes, 91 312 1-30 



Kaspberries, 1-48 4-00 0'65 



Blackberries, 1-19 4-44 1-01 



Strawberries, 1-31 5-73 0-06 



Whortleberries, 1-34 5'78 1-05 



Currants, 2-04 6-10 003 



Prunes, 89 6-26 4.88 



Gooseberries, 145 7'15 0-05 



Pears, 0'07 7'45 6-34 



Apples, 0-75 8 37 7'47 



Sour Cherries, 1-28 8-77 1-12 



Sweet Cherries, 62 10-79 4 45 



Mulberries, 183 719 059 



Grapes. 074 1493 2-74 



CELLULOSE AND LIGNEOUS F1BEE. 



In the French Academy, during the past year, an interesting discussion 

 has been going on, concerning the probability of only one, or of several, 

 kinds of cellulose, and which we find reported in M. Nickle's correspondence 

 with S Hitman's Journal, No. 82. Payen was an advocate of the first opin- 

 ion, Fremy of the second. Judging from the action produced upon ligneous 

 tissues by Schweitzer's reagent (ammoniacal oxide of copper), Fremy ad- 

 mits, at least, two species of cellulose; for he has seen paper, and textile 

 fibres in general, dissolve in ammoniacal oxide of copper, while elder pith, 

 and ligneous fibres in general, resist its action. 



To Mr. Payen this difference seemed only an apparent one; he believed 

 that in this latter case the cellulose is incrusted with gum and foreign mat- 

 ters, which hinder the solubility ; also the pith of the elder, which is insolu- 

 ble in Schweitzer's reagent, becomes soluble in it when it has been previously 

 treated with a weak acid, such as dilute chlorohydric acid. Mr. Fremy sup- 

 posed that the chlorohydric acid does not act as a solvent of foreign matters, 

 but that it converts one variety of cellulose into the other variety, in the 

 same way, for instance, as an acid converts cane sugar into glucose. 



We need not speak of the different phases of this discussion, for it is not 

 yet settled. According to Fremy, we must admit at least two kinds of cel- 

 lulose, offering the same percentage composition, but differing from each 

 other in their chemical properties, and capable of being brought into the 

 same state by the most diverse reagents, such as mineral acids, organic 

 acids, potassa, ammonia, etc. In order to prove that the differences in the 

 properties of cellulose are due to the state of the organic substance itself, 

 and not to the presence of mineral substances, Fremy has had recourse to 

 the action of heat. In exposing vegetable pith, which is insoluble in the 

 cupreous reagent, to the action of a temperature not exceeding 30, and 

 maintaining it at that point for several hours, he has seen that substance 



