290 SELIG HECHT 
TABLE 6 
Liminal concentrations of a series of potassium salts 
SALT CONCENTRATION 
KCl 0.075 N 
KBr 0.050 N 
KI 0.010 N 
KNO; 0.15 N 
CH;COOK , 0.075 N 
KSCN 0.075 N 
TABLE 7 
SALT CONCENTRATION 
KCl 0.20 N 
CH;COOK 0.15 N 
KSCN 0.10 N 
A combination of the two tables gives an anion series of 
stimulating power as follows: 
I>Br>SCN >CH;COO >Cl>NO; 
Excepting SCN and NOs, which are not in the usual positions, 
this order agrees with the familiar Hofmeister series (Hoéber, ’14, 
p. 309). An absolutely complete agreement is hardly to be 
expected, because my tests were made in seawater. Hober (’14, 
p. 323) has constructed ‘Uebergangsreihen,’ in which he has been 
able to change the position of some members of this lyotropic 
series by altering the milieu in which the experiments were per- 
formed. Analogous to this is Cole’s (10) observation for the 
stimulation of the frog foot, in which the positions of NH, and K 
were reversed by an increase in the concentration of the solutions. 
Acids. Seawater to which acid is added, gradually returns 
to its normal hydrogen-ion concentration. Therefore, the solu- 
tions to be tested were freshly made up immediately before being 
applied to the animal. This was accomplished by having a 
stock 0.1 N solution made up in rain water, and diluting it to the 
desired concentrations with seawater. The effect of the dilution 
of the seawater is insignificant. Three acids, hydrochloric, formic 
and acetic, were tested. The following table gives the values 
which were obtained in Exp. VIII.9, typical of the others (table 8)- 
