Effects of Desiccation on the Rotifer 



Dead 



Date Alive 



January 6 



January 8 



January 8 



Janua y 9 



January lo 



January 11 o 



2 Influence of the Previous Condition of the Animals 



The preceding experiment is typical of a considerable number 

 performed and shows unmistakably that desiccation is a more or 

 less harmful condition which some rotifers are better able to resist 

 than others. That the resisting power of different individuals 

 may be influenced by the conditions to which they were exposed 

 previous to desiccation is shown by the following experiment. A 

 number of rotifers were placed in a glass dish with a little clean 

 water and were starved for three days. A number of others were 

 taken from the original culture and both lots dried under exactly 

 the same conditions and kept for the same length of time (four 

 days). Water was then applied and the percentage which recov- 

 ered noted. The following table gives the result of the experi- 

 ment : 



TABLE II 



E^ect of Starving 



This experiment shows the great caution that must be used in 

 comparing results obtained with rotifers taken from different cul- 

 tures or the same culture at different times. In all of the follow- 

 ing experiments the rotifers compared were as similar as it was 

 possible to obtain them and furthermore fairly large numbers 

 were dealt with so as to eliminate as far as possible this source of 

 error. 



