The Bt'havior of Loxophvllnni 405 



or in increased rapidity of its ordinary back and fortli movements. 

 The reactions may be less easily evoked, hut the spontaneous 

 activity of the organism is increased. 



Chemical. Owing to the small number of specimens available 

 few experiments on the reactions of Loxophyllum to chemicals 

 were tried, since they frequently produced fatal effects. Several 

 drops of water containing specimens of Loxophyllum were spread 

 out on a slide and a minute grain of salt or a small drop of weak 

 acid was placed at one edge. The Loxophylla showed no ten- 

 dency to go directly away from the diffusing chemical. Some- 

 times they would go toward it. In many cases they would move 

 about irregularly until overcome by the chemical in case it was 

 strong enough to be injurious. The majority of the individuals, 

 however, usually succeeded, sooner or later, in getting away to a 

 safe distance. When swimming toward the chemical the anterior 

 end IS more strongly stimulated and the animal swims backward, 

 turns, and goes in some other direction. The length of the back- 

 ward course being dependent on the strength of the stimulus 

 received, the animal is apt to go back further when pointed to- 

 ward the stimulus than when pointed away from it. Also excur- 

 sions toward the stimulus are more quickly checked than those in 

 other directions. In consequence of these reactions the animal 

 works its way farther from the stimulating substance. The proc- 

 ess is a slow one, especially since, owing to its natural rhythm of 

 movement, Loxophyllum frequently changes the direction of its 

 locomotion. Even when pointed directly away from the chemical 

 it does not usually go very far before backing up and turning in 

 another direction, and thus much of what was gained is lost. 

 The whole process of negative chemotaxis in this form is a very 

 slow, uncertain, and bungling one. 



In one experiment I placed a lot of Paramecia with several 

 Loxophylla, and a drop of acid was introduced at the edge of the 

 liquid containing them. The Paramecia showed a very quick 

 and marked negative reaction. The Loxophylla were incompar- 

 ably longer in getting away from the chemical. Some went toward 

 it and were killed, while practically all of the Paramecia got safelv 

 away from the injurious substance. 



