Shaking Experiments with Protozoa. 59 



Shaking for one hour in either machine showed little effect on 

 any of the species, except that Paramecium became somewhat less 

 active. With the horizontal shaker for a period of six hours, 

 Paramecium and Euglena became sluggish and this sluggishness 

 continued for several hours after removal from the machine. 

 Twenty-four hour periods gave decided results, the two species 

 just mentioned being either killed or rendered very sluggish. How- 

 ever, in all cases a few individuals were nearly normal. With 

 Stylonychia and the bacterial species, Spirillum, the case was dif- 

 ferent inasmuch as no observable deviation from normal behavior 

 was evident. The flattened shape of the former may have some- 

 thing to do with the results obtained with this form. The effects 

 of shaking lasted for at least two weeks, during which period, there 

 was a constantly decreasing number of individuals in the shaken 

 cultures which were carefully compared with check experiments from 

 " wild " forms and from the checks used with the experiment. 



In order to test the hypothesis that shaking may increase or 

 decrease the division rate in Paramecium, six individuals were 

 isolated from the twenty-four hour cultures and their condition 

 followed for seven days. During this period, the average rate of 

 fission was approximately the same as that in the check forms. 



That the sluggish movements were not the result of an emacia- 

 tion due to lack of food, by the killing of bacteria, in shaking, 

 which Paramecium uses for food, cultures were placed in sterile 

 chambers immediately after their removal from the shaker. In 

 such cases, no new bacteria were introduced. No difference was 

 manifest from the control individuals. 



Verworn, in commenting upon shaking experiments, suggests 

 that the effect is that of establishing a tetanus in the organisms 

 being experimented upon. That this explanation will scarcely 

 hold in the present species is evident from the fact that as far as 

 could be determined, the movements of the cilia and flagella were 

 normal, or at least but slightly affected. If tetanus had set in, it 

 is fair to assume that it would have reached the organs of loco- 

 motion as well as the body proper. 



Metalnikoff, Mesnil, Moulton and others have demonstrated 

 proteolytic, lipolytic and amylolytic enzymes in protozoa and the 



