286 



Society Proceedings (122). 



The relation between the conductance of the suspending fluid 

 and the net conductance of the suspension was somewhat un- 

 expected. Perrier's artificial sea- water 1 was diluted to 2, 4 and 

 8 volumes with distilled water. Chlorella which had been grown 

 in a solution somewhat more dilute, was transferred successively 

 to increasing concentrations of this artificial sea-water and the 

 net conductance determined several times in each case until upon 

 further renewal of the solution between each determination no 

 further change occurred. For example, in changing from 1/8 to 

 1/4 strength sea- water, the net conductance changed from 28.9 to 

 27.2 per cent. Corrected for the decrease in the volume of cells, 

 the figures would be 28.9 and 28.3 per cent. The change in net 

 conductance is within the limits of error of the method. This 

 shows that if by any chance the conductivity of the surrounding 

 medium is changed during the course of an experiment only the 

 net conductivity in per cent, will normally remain constant. Ex- 

 pressed in any other way the results might easily be misleading. 

 In the above case the net resistance expressed in ohms instead of 

 remaining constant fell from 80 to 45 ohms approximately. 



It is also of interest to note that the net conductance of dead 

 cells is relatively greater in those organisms which normally 

 encounter a fluctuating environment. The ratio of the net con- 

 ductances of dead and living cells is about as follows: red blood 

 cells .45, yeast .65, bacteria .70, Chlorella .80-.90. This fact 

 suggests that the cell walls (or at least some non-living structure), 

 help to protect such cells from extreme fluctuations in electrolyte 

 concentrations, insofar as the changes inside the cell walls would 

 be retarded and therefore less abrupt. Multicellular forms such 

 as Laminaria need such protection only at the outer surfaces of 

 the superficial cells, and it is therefore not surprising that such 

 tissues have when dead only about one tenth the electrical re- 

 sistance that they have when living. 



1 Perrier, E., Compies Rendus, 1890, cx, 1076. 



