1912] Lorande Loss Woodruff 407 



tions. Considered as a whole, the results of the experiments indi- 

 cate a marked parallelism between the order of toxicity of the 

 various cations toward Paramcecium and the ionic potentials of the 

 ions employed. 



VI 



Hunt's interesting experiments on the effect of small doses of 

 alcohol on mice and guinea pigs apparently indicated that animals 

 to which this substance has been administered for some time possess 

 increased susceptibility to certain poisons. It was from this point 

 of view that a series of experiments were undertaken on this cul- 

 ture of Paramcücimn}^ Experiments were planned to determine 

 the influence of small doses of alcohol on the vitality of the culture 

 as indicated by the rate of multiplication; and also to determine if 

 the animals showed increased susceptibility to copper sulphate. It 

 is impracticable to present the details of the results secured by sub- 

 jecting various subcultures to alcohol alone and to alcohol and cop- 

 per sulphate simultaneously, but it is believed that the data secured 

 Warrant the following Statements : 



Minute doses of alcohol {e. g., 1/2,500 to 4/2,500) will de- 

 crease the division rate at one period and increase it at another 

 period of the life of the culture. When alcohol increases the rate 

 of division, the effect is not long continued, but gradually diminishes 

 and finally the rate of division falls below that of the control, fol- 

 lowed by fluctuations above and below the rate of the control. An 

 increase (doubling) of the amount of alcohol administered, how- 

 ever, will again bring about more rapid cell division for a limited 

 period. The amount of alcohol has been increased (doubled) three 

 times, always with the same result. Treatment with alcohol lowers 

 the resistance of the organisms to copper sulphate {e. g., 1/1,250,- 

 000 CUSO4). 



It is of considerable interest that alcohol produces opposite 

 effects on the division rate at different periods, and this shows the 

 danger of drawing conclusions from experiments on short-period 

 cultures or on individuals about the ancestry of which little or noth- 

 ing is known and which have been isolated merely from stock cul- 



" Woodruff: Effects of alcohol on the life history of Infusoria. Biological 

 Bulletin, vol. 15, no. 2, 1908. 



