/]/) MICRO-CHEMICAL REAGENTS. 



OTHER ORGANIC COMPOUNDS. 



SOLUTION OF CANE SUGAR (Syrup). 



Vegetable cells containing much sugar often 

 assume a beautiful red color on the addition of 

 sulphuric acid. This fact has been utilized in ob- 

 taining a reaction for protoplasmic substances. 

 The tissues to be tested are first saturated with a 

 solution of cane sugar and water. On the addition 

 of sulphuric acid the red color manifests itself. 

 This reaction (Raspail's) 1 is, however, often difficult 

 to obtain, and not very good. The sections have 

 to be left in the acid for some time before the color 

 appears. 



Syrups of different degrees of concentration also 

 find application as anhydrating media. 2 A three 

 per cent, solution had been used as a fluid of prep- 

 aration in the study of transparent ovules, e. g. 

 embryo sac of Monotropa and Orchis ; and a five 

 per cent, solution has been recommended for 

 pollen-cultures under the microscope. 



1 Raspail : Chimie organique, 1839, II., p. 139. M. Schultze : Ann. der 

 Chem. u. Pharm., Bd. LXXL, p. 270. (Second discovery of the reaction.) 

 Schacht : Mikroskop, p. 27 ; Pflanzenzelle, pp. 27, 28 ; Anat. u. Physiol. 

 der Gewachse, I., pp. 46, 61. Dippel : Mikroskop, I., p. 283. Nageli : 

 Mikroskop, 1877, pp. 476, 526. Frey : Mikroskop, p. 73. Hofmeister: 

 Pflanzenzelle. Handb. der phys. Bot, I., p. 2. Weiss : Allg. Bot., I., p. 

 77. Duchartre: Elements de Bot, 2 ed., p. 25. 

 2 Strasburger: Befruchtung u. Zelltheilung, pp. 16, 29, 52, etc. 



