RESERVE CELLULOSE. 7 



PL 2, fig. 3, exhibits a view of some cells from TuVrpd fjes^itrnmn during the 

 process of solution; the section was heated with iodine; the walls at a are colorless ; 

 the musses of intercellular substance at h are brown. 



The action in weak hydrochloric acid is similar to that with sulphuric. 



Sections boiled in solutions of one part smoking acid to four of water lose the reserve 

 of their walls in three minutes. Tulipa requires five minutes' boiling for the complete 

 solution of the reserve from the walls. Sections from young stems of Primula, Begonia, 

 Tropoeoluui, and cotton-fibers were subjected to the action of acids of the above 

 strength'!, and serve to prove the different behavior of reserve cellulose towards these 

 hot solutions of acids. 



Acetic acid does not affect the reserve cellulose. Cold, weak, mineral acids act very 

 slowly. Sections of Polygonatum after four da3's in sulphuric acid, of the sti'ength which 

 was used for tiie hot acid, were scarcely affected. At the end of twenty-four days in 

 hydrochloric acid, one part acid to four of water, the walls of the endosperm cells in 

 Polygonatum were much swollen, and, in some cases, the reserve was dissolved. Allvim 

 cepa sections were not much affected after nine days in hydrochloric acid. PI. 2, figs. 

 4 and 5, illustrate the action of cold solutions of hydrochloric acid on Polygonatum. 

 Concentrated sulphuric acid dissolves the reserve cellulose and the primary membrane 

 very quickly. 



Alkalies. The endosperm of Polygonatum seeds is not visibly affected by strong or 

 weak alkalies ; when sections of the seeds are boiled in a concentrated solution their 

 walls swell slightly. 



In Colchicum seeds, the endosperm is not noticeably affected by weak or strong, cold 

 or hot caustic potash. The cell walls in the seeds of Iris pseudacorus swell slightly with 

 cold, weak caustic potash, more with strong solutions, and the action is still more marked 

 when these solutions are hot. Sc'dla slblrlca has the walls of its endosperm cells 

 strongly swollen in hot, strong caustic potash, though they swell only slightly in weak 

 solutions. Sections of Paris quadrifolia, from seeds not quite ripe, were treated with 

 hot, weak solutions of caustic potash and the thickenings were dissolved from the walls. 



The action of caustic soda upon reserve cellulose is similar to that of caustic potash. 



Solutions of Iodine. When the ripe endosperm of Polygonatum seeds is treated with 

 iodine iu potassium iodide, the tliiclcened cell walls immediately take up the reagent in 

 great quantities and become red-brown^ or, when the iodine is supplied in sufficient 

 quantities, almost black. This power of absorbing great amounts of iodine with the 

 brown reaction is characteristic of the reserve material of the walls of the endosperm 

 cells in Liliaceae, Amaryllidaceae, and Iridaceae. In only three cases are exceptions 

 found, and in these the cell walls remain colorless after treatment with the iodine, or 



