Walter Stiles 
148 
A -> M and M -> B first rise and then fall, the minimum value 
naturally occurring in the mixture of salts in which the fall of 
resistance is slowest. 
To account for these changes in the values of the velocity con¬ 
stants, Osterhout puts forward two alternative suggestions. According 
to the simpler one, the rate of the first reaction is increased by calcium 
chloride, which has a minimum influence when the molecular pro¬ 
portion of this salt to sodium chloride is 4-76 :95-24, that is, when the 
proportions are such that the resistance falls most slowly, while the 
rate of the second reaction is increased by sodium chloride, which 
also has a minimum effect when the ratio of calcium chloride mole¬ 
cules to sodium chloride molecules is 4-76 : 95-24. “It makes little 
difference whether the value of the constant is increased by the salt, 
the effect passing through a minimum, or diminished by the salt, the 
effect passing through a maximum/’ 
The alternative explanation supposes that the first reaction, 
A -> M, that is, the formation of the substance to which the tissue 
owes its resistance, is catalysed by calcium chloride, while both the 
first and second actions are retarded by the presence of a substance 
such as Na 20 XCaCl 22 formed between sodium chloride, calcium 
chloride and a constituent X of the cell, and the action is supposed 
to be reversible. The quantity of this substance present is then 
governed by the law of mass action and can be calculated from the 
equation 
CNa 20 XCaCl 22 jr 
(CNaCl) 20 C X CcaCl 2 ’ 
where the symbols Cxaci, Ccaci 2 , etc., represent the concentrations of 
the various substances concerned, and K is a constant. 
When the maximum quantity of this negative catalyst is pro¬ 
duced there will be maximum antagonism. Now, according to 
Osterhout, the position of maximum antagonism is independent of 
the absolute concentrations of the antagonistic substances, while 
the relative proportions of the salts giving a maximum quantity 
of the compound Na 20 ACaCl 22 will depend on the concentration. To 
overcome this difficulty, Osterhout assumes that the negative catalyst 
is formed at the surface, the sodium chloride being supposed to migrate 
into the surface until the surface layer is saturated, so that with 
increased concentration of the salts either inside or outside the cell, 
the concentration in the surface layer remains constant. 
It must be admitted that this is a rather tremendous super¬ 
structure of theory built on the foundation of the changes in electrical 
