82 Dr. A. D. Waller. Influence of Acids and Alkalis 



a base below optimum strength, the latter exhibiting the excessive 

 action of an acid above optimum strength. 



Partly for this reason, and partly in order to eliminate the re- 

 sistance factor, results are formulated in terms of the relative magni- 

 tude of the quotient A/K as well as in terms of the absolute 

 magnitudes of A and K. This point is illustrated by plate 2410. 



Tig. 4— Oxalic acid N/20 (2410). 



Method. — The disposition of the object of experiment is m accord- 

 ance with the diagram, and the galvanometer (dead-beat) is arranged 



Fig. 5. — Diagram of apparatus. The excised nerve rests upon two pairs of un- 

 polarisable electrodes, pp' leading in the polarising current, ee leading out 

 the extrapolar or electrotonic current. 



to give a continuous record (lasting usually from 30 to 60 minutes) 

 as described in a previous communication (Croonian Lecture, 1896, 

 ' Phil. Trans.,' B, 1897). 



