54 MINNESOTA BOTANICAL STUDIES. 



chloroform, ether, nitrous oxide and oxygen. Small quantities 

 of alcohol (methyl), ammonia (hydrate), carbon bisulphide, ether 

 and chloroform were placed in tubes inside of closed receivers 

 and allowed to vaporize into the air enclosed. The nitrous ox- 

 ide was the commercial mixture, N 2 O 90 parts, N 8.86, O 1.13. 

 In certain experiments the pure gas which had been obtained 

 from ammonium nitrate was used. Commercial oxygen from 

 tanks was used. 



As a means of control and test of the actual efficiency of the 

 reagents, leaves of Philotria (Elodea) and hairs of Tradescantia, 

 Tomato, Begonia, Pelargonium and Geranium were mounted 

 in an Engelmann gas chamber and subjected to their action. 

 These tests were carried on at a room temperature of 16 to 23 C., 

 and the results noted below are quite in harmony with those 

 given by previous writers. 



Oxygen. The movements of protoplasm are greatly acceler- 

 ated in an atmosphere of free oxygen for five to seven minutes, 

 after which the movements gradually diminish until they cease 

 entirely. If the living cell is kept under the influence of free oxy- 

 gen for considerable length of time it dies, but no apparent change 

 in the structure or behavior of the protoplasm could be noticed. 



Nitrous oxide (N 2 O). This gas has the same general effect 

 on living protoplasm as oxygen with the exception that it is less 

 and does not kill the cell even when exposed for several days 

 in an atmosphere of 90 per cent, nitrous oxide. The duration of 

 active movements varies from three to five minutes (Moeller V.). 



Chloroform and Ether. The action of these two reagents 

 are about the same. Aqueous solutions containing 1/20000 part 

 of reagents at first slightly increase the movements of the proto- 

 plasm. By increasing the strength of the solution the rapidity 

 of movement was also increased, but the reaction time was very 

 much shortened. Strong solution causes vacuolization and par- 

 alyzes the protoplasm. 



Ammonia. Weak aqueous solution containing from 1/30000 

 to 1/20000 parts of ammonia does not seem to modify the activity 

 of the protoplasm when subjected to its action for a short time 

 only. Stronger solution produces vacuolization and slightly ac- 

 celerates the movements of the protoplasm for a minute or two. 



Carbon bisulphide. The smallest possible quantity that could 

 be introduced arrested all movements. 



Alcohol. Aqueous solutions containing 1/20000 to i/ioooo 

 parts of alcohol had no visible effect upon the protoplasm. A 



