5l6 A.H. Estabrook 



Different Resistance of Young and Adults to Certain Concentrations 



Interesting results were reached in the effect of nicotine upon 

 Paramecia of different ages. Nine adult specimens were put into 

 a 1-5,000 solution of nicotine. Nine specimens just divided were 

 put into the same solution. At the end of 2 hours, 5 of the adult 

 specimens were dead, while only 2 of the young were dead. At 

 20 hours, all 9 adults were dead, while all but 2 young were alive. 

 At the end of 30 hours, all the young were dead. 



Some adult Paramecia were put into 1-20,000 nicotine. These 

 were all dead at the end of two days. Some specimens just di- 

 vided, put into the same strength of nicotine, grew to normal size 

 and lived for 5 days, but did not divide. 



Thus in these grades of nicotine the young Paramecia are more 

 resistant to the chemical than adult specimens. In NaCl, on 

 the other hand, as has been shown, the adult specimens are more 

 resistant than the young specimens. 



Summing up the results w^ith nicotine, we find that a certain 

 amount of growth takes place in the stronger solutions of nicotine, 

 though these same solutions later kill the organism. This is true 

 for solutions up to and including 1-10,000. In 1-20,000 nicotine 

 solution there was a very slight retardation of growth at late 

 stages. In the 1-30,000 solution the nicotine had no effect on the 

 growth. 



EFFECTS OF STRYCHNINE ON GROWTH 



Strychinne has long been known to be a powerful poison for 

 protoplasm. The work of Schulze, Binz, and others has shown 

 its action on Protozoa, but there are no studies as to its effect 

 upon growth in smaller quantities than lethal doses. Calkins 

 and Lieb have shown that, in small quantities, strychnine in- 

 creases the rate of division in Paramecium, but they did not study 

 its effect upon growth and size. It will be interesting to deter- 

 mine whether there is increased size at the time when the animals 

 show the increased rate of division, described by the authors 

 mentioned. The general effects of this powerful poison upon cel- 

 lular growth are likewise of interest. 



