Electromotive Force of Diphasic Liquid Systems . 103 
explanation of bio-electrical phenomena. On the physical side he fails 
altogether to substantiate his statement that salts rather than acids play the 
predominating role in the systems he investigates. A careful review of the 
experimental evidence shows that the differences of potential which he 
obtains can be correlated with a difference of hydrogen ion concentration 
whenever free acid is present in the ‘ oil and that the theory'of salt action 
is derived from a misinterpretation of the complex chemical systems with 
which he deals. 
On the biological side Beutner lays himself open to serious criticism. 
He claims to have superseded such unproved theories as that of differential 
permeability by a theory resting on clearly ascertained facts ; but on 
examination these ‘ facts ’ prove to be little more than a reintroduction 
of the lipoid theory without consideration of any of the difficulties which 
this theory has already encountered, and in his attempt to provide a solution 
for particular problems—in his theory of the current of injury and in the 
analogy which he appears to seek between cuticle such as apple-skin and 
the plasma membrane of the cell—Beutner assumes a simplicity and 
uniformity of structure for the living organism to which no physiologist can 
give countenance. 
