CHARLES E. BILLS. 



around one tenth per cent, is serviceable; however, the margin 

 between the narcotizing and lethal doses is so small that great pre- 

 cautions are necessary in its use. 



In studying the action of several of the aliphatic alcohols the 

 writer has observed that in propyl and iso propyl alcohols of cer- 

 tain dilution a balance of effects obtains such that the external 

 (locomotor) cilia of Paramecium are inactivated before the internal 

 activities of the animal are changed. Locomotion, therefore, can 

 be reduced or stopped without appreciably affecting any of the 

 visible activities which obtain within the animal itself. 



In narcotization a single paramecium is added to a drop of the 

 alcohol solution ; or, better, one volume of a rich culture of mixed 

 races is quickly and intimately combined with one volume of the 

 alcohol of double the desired strength. For class demonstrations 

 a number of cubic centimeters should be prepared by the latter 

 method half an hour in advance and distributed to the students for 

 study. The narcotized protozoa may then be observed under a 

 cover glass or directly with a water immersion lens. When the 

 animals come in contact with the stronger alcohol a few are im- 

 mediately killed, while the majority at first exhibit avoiding reac- 

 tions they move erratically, become frequently bent in at the peri- 

 stome, and may discharge a few trichocysts ; then, as these reac- 

 tions to the new stimulus cease, they become paralyzed and settle 

 to the bottom. This final effect obtains in approximately half an 

 hour from the application of the alcohol, the time varying with the 

 race and condition of the individuals. The completely paralyzed 

 paramecia exhibit little or no ciliary activity on the body, yet the 

 cilia in the oral groove and at the peristome maintain a vigorous 

 and coordinated movement ; the undulating membrane of the oeso- 

 phagus continues to direct the ingestion of food in approximately 

 the normal manner; and the activities of the contractile vacuoles, 

 food vacuoles and streaming protoplasm remain apparently normal 

 for an extended period. With careful manipulation the narcosis 

 can be continued for four or five hours, and these activities can be 

 gradually retarded by heavy or prolonged narcotization. Thus it 

 is evident that the study of Paramecium is greatly facilitated by 

 the use of propyl alcohol as a narcotizing agent. 



Paralysis is induced by the action of the alcohol on the cilia. 



