610 Price.— Some Studies on the Structure of the Plant Cell 
The wall is not quite homogeneous, however, as fairly numerous bright 
spots appear on its surface with clear spaces between. Observations in this 
case were made with sunlight, a Nernst lamp, which was first used, showing 
little but sap particles and indications of a protoplasmic movement. In 
sunlight the protoplasmic particles were generally rather small and arranged 
in different layers. On focusing at the outside, there appeared first within 
the wall very minute particles with a rapid Brownian movement and a large 
path of motion. Within this layer, forming presumably the chief mass of 
the protoplasm, are larger and more numerous particles also with a strong 
Brownian movement. The sap particles come into focus in the lower plane, 
and these are seen to be of quite another order of magnitude, with a more 
sluggish Brownian movement. They are generally elliptical or rod-shaped, 
much as in Elodea. 
The dead hairs show the protoplasm quite motionless, and coagulated 
into a mass, containing large relatively bright particles. 
Salvinia . 
The hairs which clothe the filamentous segments of the submerged 
leaves show a slightly heterogeneous wall, while the protoplasm contains 
particles which have an oscillating movement. The material is fairly 
suitable for plasmolysis experiments. 
(b) Root Hairs. 
Root hairs have been successfully used for experiments on plasmolysis, 
and attempts have been made to see whether they would be suitable for 
work with this method. Generally, however, they are difficult to mount 
satisfactorily, and the torn or crushed tissues to which they are attached 
often interfere with observation, while colloid particles escape into the liquid 
and fill the field. 
Mustard. 
Mustard seeds were germinated on damp blotting-paper, and the root 
hairs were mounted with a small piece of the root, with as little injury to 
the hairs as possible (Price, T2). The protoplasm is abundant towards 
the tip of the root hair, and ‘ plugs 5 of various sizes occur along its length. 
The distal end of each plug generally shows small particles in motion, while 
motionless particles occur towards the basal end. 
The appearance is on the whole very similar to that already described 
for fungal hyphae. Only a few particles of the nature of sap inclusions 
occur in these hairs. 
