Epidermis of Mesembryanthemum pseudotruncatellum. 1141 
The epidermis is easily removable from all parts of the plant. A moist 
chamber was constructed according to the instructions of Haberlandt, and 
the epidermis was examined by means of the ‘ Linsenversuch' of this 
author. 
As an object, a cross made of black card was used. Before treating 
with HC1 the cells in all cases formed faint images of the cross a very 
small distance beyond the basal wall. In the living condition this wall is 
lined by a thin layer of protoplasm, the nucleus occupying a central position 
in it. This is, therefore, fully illuminated, a darker area surrounding it. 
Fig. 6 . Cell from upper epidermis in 
longitudinal section. 
Fig. 7. Cell from side epidermis in 
longitudinal section. 
After treatment with HC 1 brilliant and sharp images were obtained, 
while the whole of the cell floor became illuminated. 
In a similar experiment with the epidermis of the sides it was found 
that the image formed before removal of the calcium oxalate encrustation, 
although still faint and blurred, was very much better developed than in 
the case of the cells of the upper epidermis. The conclusion is, therefore, 
that in structure the epidermal cells are all well-developed lens-cells and 
capable of forming as definite images as those described by Haberlandt, 
v. Guttenberg, and other authors. 
Further, owing to their structure, the cells of the side epidermis are 
much more efficient lens-cells than those of the upper epidermis. In both 
