EFFECT OF ETHER AND CHLOROFORM 49 



70. Oxidizing Effect of Hydrogen Peroxide. Repeat 69 using 

 .5 per-cent, 1 per-cent, 3 per-cent, and 6 per-cent. solutions of 

 hydrogen peroxide. 



71. Catalytic Poisons. A number of compounds of the hydro- 

 carbons which are not acid or basic, or very active chemically, 

 are poisonous by their presence ; inducing chemical changes in 

 the plasma without participating in this action themselves. The 

 intensity of the action of compounds of this class seem to 

 increase with their molecular complexity. The influence of 

 these substances seems to consist in setting up new molecu- 

 lar disturbances in the compounds with which they come in con- 

 tact, without actually entering into any chemical combination 

 with them. Their influence is likened to the behavior of a row 

 of blocks set up in such manner that the falling of the first 

 one throws down the second, which in turn knocks down the 

 third until the whole row is prostrate. The impulse com- 

 municated to the first molecule is communicated to the others 

 until the entire mass is affected. Among the catalytic poisons 

 are ether, alcohol, chloroform, chloral, carbon disulphide and 

 many others. 



72. Effect of Ether and Chloroform on Movement. Pour enough 

 ether into a wash bottle to form a layer 5 cm. deep on top of an 

 equal amount of water previously added. Connect the outlet 

 with one of the tubes of an Engelmann gas chamber, and run a 

 rubber tube from the other side of the gas chamber to a filter 

 pump or an air pump. The tubes in the wash bottle should be 

 arranged so that air will be drawn in through the wash bottle by 

 a tube extending below the surface of the ether. The stream of 

 air bubbling up through this becomes charged with ether vapor and 

 is then drawn through the chamber. Mount a specimen show- 

 ing movement of protoplasm, on a cover-glass, and invert over 

 opening of gas chamber. Open a pump and allow a stream of 

 vapor to pass through. Note cessation of movement. Open the 

 chamber and allow access of air. Note resumption of move- 

 ment. Repeat with chloroform. 



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