Certain Effects of Salts on T H E Penetration of Brilliant Cresy-l Blue into Nitella. by Marian Irwin

The effect of salts on the rate of penetration of dye into living cells has been studied by various investigators I by comparing the rate in dye solution containing salt with that in dye solution containing no salt, but it is not possible to determine from their results whether the salt acts on the protoplasm or on the dye or on both. The writer therefore has suggested a method ~,3 by which we are able to separate the effect of salt on the protoplasm from that on the dye. This is done as follows: (1) Cells are placed for a given time in a salt solution, after which they are placed in dye solution containing no salt. The rate of penetration of dye in the case of such cells is compared with that of the control (cells which have not been previously exposed to the salt solution). This gives the effect of salt on the protoplasm since it has previously been shown 2,3 that there is no error due to salt adhering to the surface of the cell wall (which cannot be removed by wiping and washing). I t might be thought that an error could arise from the fact that salt might diffuse out from the cell when removed from the salt solution and placed in the dye solution