48 INFLUENCE OF CHEMICALS 



more or less constant union of oxygen with material held in the 

 plasma, or of the living substance itself. As long as this oxida- 

 tion is attended by renewal with unoxidized fresh material no 

 disturbance occurs. If however the supply of food is cut off, 

 the continued release of energy diminishes the mass of the living 

 substance and starvation phenomena ensue, comprising other 

 effects beside that from lack of food, however. When protoplasm 

 is brought into contact with compounds readily yielding their 

 oxygen it unites with this substance, burning up very quickly. 

 It is to be noted however that this oxidation is not simply an in- 

 crease of the processes normally in action in the plant, but new 

 oxidations, are set up which reduce the whole machinery of the 

 living matter to a form from which nearly all energy has been 

 lost. The consistency and appearance of the injured protoplasm 

 will be unlike in the two instances. 



67. Starvation. Place some fresh filaments of Spirogyra in a 

 deep dish rilled with distilled water entirely free from sediment. 

 Allow it to remain in this liquid for several days, and note general 

 appearance from day to day. Two weeks later, or as soon as the 

 filaments have begun to deteriorate, examine the structure of the 

 cells with a magnification of 300 to 600 diameters. Reserve ma- 

 terial will be seen to have disappeared, the nucleus will have lost 

 its sharp contour and drops of oil will be apparent. 



68. Oxidizing Effect of Potassium Permanganate. Place a 

 number of healthy filaments of any species of Spirogyra in a .2 

 per-cent. solution of potassium permanganate and keep under 

 observation with the microscope for ten minutes. Wash in clear 

 water and examine ; if alive restore to a culture dish and note 

 appearance a day later. Treat the same preparation with a .5 

 per-cent. solution, and note results ten minutes after immersion. 



69. Oxidizing Effect of Potafcsium Chlorate. This compound 

 causes oxidation in living matter only, under ordinary circum- 

 stances, while the permanganate attacks all organic matter. Treat 

 Spirogyra with .5 per-cent, I per-cent. and 3 per-cent. solutions 

 and note results in ten and twenty minutes after exposure. 



