W. J. V. OSTERHOUT 



517 



NaCl by inhibiting the fall of resistance which occurs in pure NaCl, 



The upper curve (2 hours) shows even more pronounced antagonism. 



The results with caffeine (Fig. 2) are similar except that the curve 



does not fall as rapidly with increasing concentrations of alkaloid. 



06 n 



Fig. 2. Curves showing antagonism between NaCl and caffeine. Ordinates 

 represent net electrical resistance of Laminaria (expressed as per cent of the 

 normal); abscissae represent concentrations of caffeine added to 0.52 m NaCl. 

 The resistance of the control at 18| hours was 96 per cent. Average of two 

 experiments; probable error less than 5 per cent of the mean. 



With cevadine (Fig. 3) the curve falls much more rapidly, the maxi- 

 mum being in the neighborhood of 0.005 m cevadine sulfate. Here 

 death is more rapid, the tissue being killed in 18 hours or less, even 

 in the most favorable solution. 



The experiments with cevadine were carried out during the day 

 at 15 ± 2°, and the time curves in the various solutions follow more 



