486 
S. C. BROOKS 
U-tube was placed in a constantly stirred water bath, whose tem- 
perature was determined to within o.i° C, and the conductance de- 
termined by means of the ordinary arrangement of a slide-wire bridge, 
Nernst string inductorium, standard i,ooo-ohm coil and telephone 
receiver. The error was less than i percent. The fluctuations in 
temperature were not great enough to justify the introduction of a 
temperature correction. 
Fig. I. 
In the later experiments it was found that the parchment thimbles 
could be omitted, with a corresponding gain in the accuracy of the 
readings. The conductance was then determined between the two 
electrodes, now immersed directly in the solution. This fact prevents 
the direct comparison of readings taken by the different methods, 
but, as the comparative values remain unchanged, does not destroy 
the significance of the experiments. 
It is obvious that the total increase in the conductance of the 
distilled water in contact with material which has been immersed 
in a salt solution will measure not only exosmosis from the proto- 
plasm, but also diffusion from the intercellular material {i. e., all non- 
protoplasmic material, including cell walls and intercellular spaces). 
This diffusion from intercellular material will change the conductance 
