264 Dr Shearer, The action of electrolytes on the 



dead. If they are only allowed to remain in the NaCl for a short 

 time and then transferred to neutral Ringer again they immediately 

 return to their normal resistance and grow freely on subculture. 



If when the resistance of the bacterial emulsion has fallen in 

 NaCl solution a little CaCL is added it again regains its normal 

 conductivity and is uninjured. Thus we get the usual antagonistic 

 action of CaCla to NaCl. It was found that KCl, LiCl, MgCl^ 

 acted like NaCl in reducing the resistance offered by the bacteria, 

 while BaCls, SrClg have no action on the resistance but act like 

 CaClg. Thus it is clear that in the bacteria as with so many other 

 plant and animal cells the entrance of the ions of NaCl, KCl, 

 LiCl, MgCla is prevented by the presence of very small quantities 

 of CaCL, BaCla or SrClg. Bacterial emulsions made up in BaClo, 

 SrCla and CaClg , having the same conductivity as Ringer's solution, 

 showed no change in resistance on being kept in these solutions 

 for some time, invariably remaining normal. 



The interest of these experiments consists in that they agree 

 completely with the results obtained by Loeb, Osterhout and a 

 large number of other workers on animal and plant cells. 



In Laminaria, Osterhout finds with CaCL and presumably also 

 with BaCla and SrCl.. there is invariably a brief temporary rise in 

 resistance when placed in these solutions of the same conductivity 

 as sea-water which is followed by a gradual fall. With the bacterial 

 cell no such preliminary rise can be distinguished, w^hile the fall 

 due to the toxic action of the solution is much delayed and slower. 



In view of the remarkable action of tri-valent ions on artificial 

 membranes as shown by the work of Perrin, Girard and Mines, and 

 the action on the permeability of cell wall as shown by the work 

 of Mines, Osterhout and Gray, it is of great interest to consider 

 their action on the bacterial cell. 



While the tri-valent positive ion of lanthanium nitrate brings 

 about a rapid rise of resistance in Laminaria according to Osterhout 

 and in the Echinoderm egg according to Gray, when this salt is 

 used in such dilution as not to affect the conductivity of the solu- 

 tion itself, no such action can be distinguished in the case of 

 bacteria by means of the Kohlrausch method. The resistance 

 remains unchanged until it begins to fall on account of the in- 

 creasing strength of the salt added. In the same way the positive 

 tri-valent ions of CeCL, neo-ytterbium chloride and the tri-valent 

 negative ions of sodium citrate appear to have no action in in- 

 creasing or decreasing the resistance of the bacterial cell as deter- 

 mined by the conductivity method. It should be pointed out that 

 these salts can only be used in very dilute solutions. In the case 

 of lanthanium nitrate this salt readily flocculates living bacteria 

 Avhen used in stronger solutions than ^ y\j^ M. 



It would seem remarkable in view of the sharp action of La on 



