Wenham, on the Vegetable Cell 3 
matical position, for in microscopical investigation there is 
some risk in even trusting solely to the evidence of eyesight, 
and it frequently happens that a series of real facts may be so 
arranged as to form the basis of a false theory. 
In the last number of the ' Quarterly Journal of Microscopical 
Science,' I described an instance wherein I had observed the 
growth and thickening of a cell wall to be c aused by the de- 
posit of a mass of active corpuscles, the so-called protoplasm.* 
It is from this mysterious vital substance that all the cell tis- 
sues of the vegetable world are built ! The starch and chlo- 
rophyll contained in the cell cavities, are also seen to derive 
their increase of bulk by the deposit of the same material. If 
any portion of a vegetable tissue (particularly if consisting of 
a group of young cells) be placed in the compressor with a 
very small quantity of water, and examined under a high power, 
by applying sufficient force the mass will burst, and as the 
protoplasm flows forth the following peculiarities may be 
observed. It is not soluble in water, but only diffuses itself 
therein ; it is in all cases materially composed of active 
particles, the size of which differ extremely in various 
plants ; in some of the lower Cryptogamia, the particles con- 
stituting the protoplasm are exceedingly minute, but with 
a large aperture and good illumination the whole is still 
seen to be chiefly composed of an assemblage of active 
molecules. 
Protoplasm, when flowing from the living plant into the 
surrounding water, exhibits a remarkable tendency to separate 
itself into cavities and ramifications, which speedily acquire 
some degree of consistency, apparently from the formation of 
a membrane, by the partial coagulation of the external 
portion exposed to water, \yhen the ramifications become so 
much attenuated, as only to allow the passage of a few active 
particles at a time, the lateral vibrations of these become 
restricted, and they travel some distance either backwards or 
forwards, in a manner very much resembling a single cur- 
rent of sap in the living vegetable cell. At the point where 
the cells have been ruptured, the protoplasm will sometimes 
form a membraneous tube, through which the discharge takes 
place. 
Protoplasm exists in a dormant state of vitality in seeds 
and dried roots, and many pollen granules appear to be simple 
vesicles filled with this substance, the molecules being more 
decidedly marked for partial drying. When a pollen grain 
* The substance termed sarcode, composing the vital tissue of some of 
the lowest orders of animals (such as Ilydra viridis), bears a remarkable 
resemblance, in some respects, to vegetable protoplasm. 
b 2 
