242 



Merkel Henry Jacobs 



b Effect of Temperature at which Drying Occurs 



From the results obtained in the preceding experiment it might 

 be thought that rotifers dried at a high temperature would show a 

 greater mortality than those dried at a low one on account of the 

 more rapid evaporation of the water. Strangely enough, this is 

 not the case. In two parallel experiments in which all of the con- 

 ditions are the same except the temperature at which the drying 

 occurs, the rotifers dried at the higher temperatures always show 

 the higher percentage as well as the greater rapidity of recovery. 

 This relation was found many times. The following are two 

 typical experiments. In the first one a moderate amount of sand 

 was present; in the second the rotifers were dried in clean dishes, 

 without any foreign matter. In both cases after the drying was 

 complete, the dishes were allowed to remain covered at room 

 temperature for four days before the apphcation of water. 



TABLE V 



E^ect of temperature at which drying occurs. Sand present 



Number of individuals 



Dried at room temperature 



fairly rapidly 



Dried at 40° in desiccator 



Dried at 40° in covered dish. . 



First movements 



Percentage of 

 recoveries 



no movements m 40 

 minutes 

 20 minutes 

 7 minutes 



5 

 65 

 93 



These experiments do not form an exception to the rule stated 

 above that rapid drying is more injurious than slow drying. Other 

 things being equal rapid drying is the more injurious. This is seen 

 in Table V. The rotifers dried in the desiccator at 40° showed a 



