Effect of Chemicals on Growth 

 Effects of Strychnine upon Adult Paramecia 



517 



A j^^Q solution of strychnine nitrate was made by dissolvin 

 .0387 grams of that salt in 1,000 cc. of distilled water. This solu 

 tion then contained about one part of strychnine nitrate m 2,50 

 of water. As this was the strongest solution used, other strength 

 desired were made by further dilution of this with hay infusion 



The 1-2,500 solution of strychnine killed Paramecia in a vet) 

 few minutes. A 1-12,500 solution caused them to swell up and 

 become vacoulated almost immediately, although they remained 

 alive and moving for several hours. With more dilute solutions 

 the effect is not so immediate or marked. To determine the 

 effect of the more dilute solutions, watch glass preparations (as 

 with NaCl and nicotine) were made. Strengths of strychnine 

 up to 1-37,500 killed a great many of the Paramecia. In the 

 1-50,000 there were as many at the end of 48 hours as at the be- 

 ginning. The normal rate of division was maintained in the 

 1-125,000 and more dilute solutions. There was no effect at 

 any time upon the size (see table XXIV). 



TABLE XXIV 



Table showing rate of division of Paramecia in di^erent strengths of strychnine and :n hay infusion. 100 

 specimens in each watch glass at beginning. 



