24 
AMERICAN JOURNAL OF BOTANY 
[Vol. 9 
the water when the walls are punctured; in others the contents ' diffuse 
rapidly. In one case, that of Chara, this diffusion is so rapid and perfect 
that it is impossible to follow the movement under the microscope; the 
flow is not checked and the cells die. In all other cases in which the con- 
tents diffuse in the water, the flow is checked by the accumulation of par- 
ticles and plastids in the opening, and healing proceeds normally. 
When the protoplasm fails to diffuse in the water the film formed does 
not seem like a plasma membrane, but more nearly of the nature of a contact 
film. This is suggested by the fact that this film does not function in any 
active healing process, although the enclosing protoplasm is in close com- 
munication with the protoplasm of the cell. Again a new plasma membrane 
is formed slowly within the cell by growth from the old membrane. The 
present experiment has not revealed the exact origin of this membrane ; but 
it seems probable that, in puncturing, a certain radius of the plasma mem- 
brane is injured, and that the new membrane begins to form at the outer 
margin of this region as an outgrowth of the original membrane. 
In many cases a cell was torn or cut near one end. In the majority of 
such cases the major portion of the protoplasm immediately escaped through 
the open end, resulting in the final death of the cell. In one or two Chaeto- 
morpha cells, a portion of the protoplasm which failed to escape formed an 
ovoid or globular mass next to the injured cell. This mass of protoplasm 
was covered by a delicate film, but a wall never developed, as has been 
described by Topler in his experiments with Bornetia. The mass dis- 
integrated in two or three days. 
It is a little difficult to determine Seifriz's exact meaning in his discussion 
of his only experiment with a cell wall, that of the pollen tube, for when 
discussing the experiment he says : 
The membrane formed in repairing a tear is of the same character as the original. This 
is not true in those instances where the wall is of cellulose, as in pollen tubes and plant 
embryos; for the enclosing surface layer of protoplasm is but a transformed portion of the 
living substance, the result of an immediate conversion of liquid plasma into a rigid gel of 
greater molar concentration (Pfeffer, 1891, p. 194). 
In this statement he has failed to draw a clear distinction between the 
cell wall, the plasma membrane, and the film formed over the exuded 
protoplasm. 
From the experiments on the living algal cells which have nonmiscible 
protoplasm, it would seem that the film formed has no functional value, 
but later an internal membrane develops which subsequently forms a new 
cell wall. Certainly my experiments on the algal cell do not substantiate 
Seifriz's statement that 
Miscibility precludes the presence of a membrane. Normal protoplasm is always 
capable of membrane formation. Therefore normal protoplasm can at no time be miscible. 
