Voi^. 6, 1920 
CHEMISTRY: F. E. BARTELL 
307 
Anomalous osmose has been observed with membranes of inorganic 
materials, such as unglazed porcelain ^ and finely divided metals ;2 with 
membranes of plant tissue, such as parchment paper ;^ with membranes of 
animal tissue, such as gold beaters skin,^ and with membranes of organic 
gelatinous materials, such as gelatine and collodion.^ The writer has in- 
vestigated each of these types of membranes and has noted their behavior 
when used with different types of solutions. Measurements have included 
osmotic pressure, the sign of the charge which exists between the membrane 
material and the solution, and the difference in potential which exists be- 
tween the two solutions in contact with the faces of the membrane. 
In order to account for abnormal osmotic effects, the following postulates 
have been made : 
1. Capillary pores connect the two faces of an osmotic membrane. 
These pores become filled with liquid from the solutions bathing the mem- 
brane faces. 
2. An electrical double layer may exist between the walls of the capillary 
pores and the liquid within them (i.e., the Helmholtz electrical layer). 
The magnitude of the electrical double layer depends upon the extent of 
the selective adsorption of the ions. 
3. A difference of potential may exist between the two faces of the mem- 
brane. The magnitude of this value is primarily dependent upon dift'usion, 
relative ionic migration velocities, and relative ionic adsorption. 
4. The forces tending to produce anomalous osmose operate in practi- 
cally the same manner as do the forces in the phenomena of electrical os- 
mose. The passage of liquid through the membrane is, in each of these 
cases, due to the electrical potential which is operative between the two 
faces of the membrane and which acts upon the charged liquid layer along 
the capillary wall. 
5. In an osmotic system there is always operative a force tending to 
produce normal positive osmose. When solutions of electrolytes are used 
there may exist, in addition to this normal force, another force acting 
either with or against it, with the result that observed osmotic pressures 
may be either abnormally great or abnormally small. 
Electrical States Which May Be Associated with the Membrane System. — • 
According to the postulates above outlined, nine different states of elec- 
trification may exist within the osmotic system. Each of the following 
diagrams represents the electrical influences associated with a single pore 
extending through a membrane; this includes the sign of the electrostatic 
charge on the pore wall with the corresponding opposite charge of the 
liquid layer bathing this pore wall, together with the orientation of the 
electrical potential existing between the two faces of the membrane. The 
concentrated solution is in every case represented on the upper side. In 
each case the arrow at the left pointing upward indicates the direction 
of the tendency to produce normal osmose, while the arrow on the right 
