62 
INTERCELLULAR RELATIONS OF PROTOPLASTS. 
and the anatomical isolation which has been ascribed to the 
vegetable cell is also to be shown to be but a partial truth, 
if, indeed, it be a truth at all. 
The vital basis of the plant-cell is its protoplasm, a name 
given to it by von Mohl in 1851. So long ago as 1868, Max 
Schultze showed' 1 ' that vegetable protoplasm and animal 
sarcodef are one and the same thing. To this identic 
substance Huxley has given the very happy title of the 
“Physical Basis of Life,” while Dr. Lionel Beale has 
suggested the somewhat broader name of Bioplasm to be 
applied alike to animal and vegetable protoplasm. Living, 
it possesses alike in animal and vegetable form certain 
special characteristics—assimilative and constructive energy, 
spontaneous motility (contractility), water absorptive power, 
and coagulability with various reagents ; while dead it has 
cumulative action with staining matters. 
Exactly like, then, as animal and vegetable protoplasm 
fundamentally are, the vegetable cell, in at least all except 
its most primitive forms, has been by biologists looked 
upon as a thing sui generis, in having the property of closely 
investing itself with a wall, secreted by the activity of its 
own protoplasm, a wall carbohydrate in its chemical nature, 
closely analogous with starch, a “cell-wall” of cellulose, 
as it is called, by which each particle of protoplasm has 
imprisoned itself and cut itself off from contact, and thereby, 
apparently, from close physiological connection with its 
neighbours ; a wall, by diffusion through which, except in 
a few well-marked cases, was the only method of the 
intercommunication of cell-contents; a wall, which acts 
towards the individual cell as an exoskeleton, in a manner 
analogous to the cliitinous envelope which invests the bodies, 
etc., of the insecta. Even the possession of a cell-wall is not, 
however, exclusively a vegetable function. Fat cells and 
epithelial cells have an external investment, totally unlike, 
however, that of the plant-cell, while Bergli lias recently 
shown that in the Cilia fiagcllata a cell wall much more 
closely resembling that in plants is present. 
The greater part of our knowledge of protoplasm in its 
relations with the cell-wall has been derived from the study 
of protoplasm in its contracted state. At all times, and 
especially so in cells which are actively growing, the protoplasm 
* Sclmltze, “Ueber das Protoplasma der Rhizopoden und Pflanzen- 
zellen.” 
f Sarcode.—Name given by Dujardin in 1835 to the contractile, 
structureless, semi fluid substance which forms the body of many of 
the lowest members of the animal kingdom. 
