O. L. INMAN 



173 



is found at the end of 20 hours to be still normal. Where complete 

 recovery was observ^ed the alg^e were planted upon agar plates and 

 they grew and formed colonies in the normal manner. 



Curves G and F show that there is no partial recovery but a con- 

 tinued state of diminished metabolism which lasts over a considerable 

 number of hours as shown by the curves. 



lOO-j 



O 10 20 



Hours 



Fig. 1. Curves showing recovery of Chlorella from the effects of a hypertonic 

 balanced solution of NaCl plus CaCl2. Curve A shows the degree of recovery 

 after an exposure of 60 minutes to a solution containing 50 cc. NaCl 1 M to each 

 cc. of CaCU 1 m; Curve D, after an exposure of 78 minutes to the same solution; 

 Curve C, after an exposure of 48 minutes to a solution containing 50 cc. NaCl 

 1.25 M to each cc. of CaCIj 1.25 m; Curve B, after an exposure of 96 minutes to 

 the last mentioned solution. The first point on each curve denotes the per cent 

 to which the respiration had fallen when the algae were transferred from the 

 solution to the normal medium. The ordinates represent the rate of production 

 of CO2 expressed as per cent of the normal; the abscissae, time in hours. Each 

 curve represents a typical experiment. 



Curves D and E show that when the respiration has fallen to about 

 38 per cent of the normal, as the result of the exposure to chloroform, 

 there is no recovery after removal from the chloroform, but, on the 

 contrary, a gradual decrease in the rate. 



Experiments were next undertaken to decide whether partial 

 recovery meant that some of the cells had been killed and others had 

 remained uninjured, or whether all the cells remained alive but had 



