SUGARS. S/ 



many fungi, and is shown especially well in asci of 

 Peziza vesiculosa, and various other ascomycetes. 

 W. T.] 



DEXTRIN. 



This transformation-product of starch may be 

 recognized in the vegetable cell by Trommer's test 

 (p. 36). The vermilion precipitate is finely gran- 

 ular, and shows the Brownian movement very 

 plainly (Cf. grape sugar). 



GRAPE SUGAR (Dextrose, Glucose) 



May be recognized by either Trommer's or Feh- 

 ling's test (p. 36). The reaction, which in general 

 is not very sure, is manifested by a reddish-yellow 

 precipitate of cuprous oxide. Barfoed's test, 1 i. e. 

 heating with an aqueous solution of neutral acetate 

 of copper, gives after long standing a red precipi- 

 tate. Such a precipitate is not formed with dex- 

 trine. At ordinary temperatures glucose gives a 

 precipitate with neutral acetate of copper, while 

 dextrine remains clear for a long time. With very 

 dilute alkaline nitrate of silver (i : 100,000) glucose 

 gives a brown color (p. 41). 



i Zeitschr. f. anal. Chemie, Bd. XII., p. 27. Sachsse : Farbst, Kohlen- 

 hydrate u. Proteinsubst, 1877, p. 192. I have not myself tested this 

 reaction, but it is deserving of mention here, since macro-chemical reactions 

 are often useful in micro-chemistry. 



