PROTOPLASM. 



paragraph 37, and Starch, paragraph 69). The thicker the layers of 

 water are, the more watery is the protoplasm, and vice versa. 



(e) Tests. 1. If a protoplasmic mass is moistened with a solution of 

 iodine, it at once assumes a deep yellow or brown color. 



2. If treated with a solution of copper sulphate and afterward-* with 

 potash, it assumes a dark violet color. 



* f 



Fig. 2. Parenchyma cells from the central cortical layer of the root of FrUittati^ 

 ii/tpenalis, longitudinal sections. A, very young cells lying closu above the apex of 

 tlie root, still without cell sap or vacuoles. B, cells of the same description about 

 i wo millimetres above the apex of the root ; by the entrance of cell sap the vacuoles 

 , s, s have been Conned. G, cells of the same description about seven to eight mil- 

 limetres above the apex of the root. In all the figures, A, cell-wall ; p, protoplasm ; 

 &, nucleus ; kk, nucleoli ; s, vacuoles ; sey, swelling of the nucleus under the influ- 

 ence of the water in preparing the specimen. X 500. After Sachs. 



8. Treated with a solution of sugar, and afterwards with sulphuric 

 acid, it becomes rose-red. 



4. The presence of protoplasm may be demonstrated in a tissue by 

 the application of various staining fluids, as magenta, carmine, etc. 



