214 PRACTICAL BOTANY 



Cut thin sections with a dry razor from the endo- 

 sperm of the dry seed of Strychnos Nux-vomica : first 

 mount a section in glycerine, and observe, under a 

 high power, the dense protoplasmic body of each cell 

 surrounded by a thick cellulose wall. 



Mount other sections in tincture of iodine not 

 diluted with water: then place a small drop of water 

 at the edge of the cover-slip, drawing it under by means 

 of blotting-paper : observe the edges 'of the section 

 where the effect of the dilution will first appear, and 

 as the cell-walls swell, it will be seen that they are 

 traversed by fine threads of protoplasm, which are 

 stained by the reagent. 



Another method has been found to succeed well 

 in demonstrating continuity through the cell-walls 

 of the endosperm of various Palms, in which the 

 endosperm has thick pitted walls consisting of reserve 

 cellulose : it is, to immerse the fresh sections in sulphuric 

 acid in which a small quantity of powdered Hoffmann's 

 blue has been dissolved : when the sections are suffici- 

 ently acted upon, wash them with water and mount in 

 glycerine. The protoplasm will be stained a deep blue, 

 and the swollen cell-wall is not stained : examine the 

 swollen pit-membranes, and if the treatment has been 

 successful they may be seen to be traversed by fine 

 curved strands of stained protoplasm. 



The tissues of the cortex of Rhamnus have been found to be 

 good material for the demonstration of continuity of protoplasm. 



