6i8 



Lorande Loss Woodruff. 



below that of the control, and at this point the infusorians 

 were again stimulated, as previously, for thirty minutes. This 

 apparently accelerated the rate (as compared with the control), 

 but only temporarily as in the eighth period it was again below 

 the control. Another stimulation at this time again raised the 

 rate, but as in the previous case the effect was not lasting. After 



Potassium Phosphate (Dibasic). 



12 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 

 3.0 



2.5 



20 



1.5 



1.0 



0.5 



0.0 



July 1904 



August 



Diagram IX. 



September 



This diagram shows the continuation of the experiment with K2HPO4 yji^g (c/. Diagram VIII) 

 illustrating the effect of stimulation with this salt at different periods in the life-cycle. Method of 

 plotting, as in Diagram VIII. Control = continuous line; regular K2HPO4 series = broken line; 

 new series stimulated = dotted line; time of stimulation = • . The figures above the diagram indicate 

 the five-day periods. (See text.) 



two more periods had passed, in each of which the stimulated line 

 was dividing at a rate below the control, they were treated still 

 another time with the salt-solution; but this time no acceleration 

 was produced, but instead the rate, as compared with the control 

 (<:/. Diagram IX), fell still lower. The behavior of the culture 

 here suggested the possibility that the lack of effect of the salt 



