448 BOTANICAL GAZETTE [JUNE 
of sea water is placed on it; bits of cover glass (hk, #) are then 
thickly covered with vaseline, and pressed down upon it to hold 
it in place. The outer cylinder is smeared with vaseline and sea 
water is then poured into a funnel which is connected by a rubber 
tube with the inlet tube (b); as soon as all the air has been expelled 
from this tube and the chamber is so full of sea water that the 
surface of the liquid is decidedly convex, the cover glass (with the 
attached root tip) is inverted and pressed down upon the outer 
cylinder in the manner shown in the figure. Care should be taken 
during the subsequent irrigation not to admit air to the inlet 
tube. 
Fics. 3-5.—Optical section of young 
root hate ‘cll : Zostera marina caaipeagg 
matic); fig. 4, the cell s' i 
after ema with dudikd * water lie: 
grammatic); fig. 5, the cell shown in fig. 
4 after more prolonged treatment with 
distilled water (diagrammatic). 
After being placed in the chamber, the root tips were irrigated 
for a time with sea water while camera lucida sketches were made 
of root hairs in various stages of development. Each of the cells 
which had been sketched was than kept under observation during 
the subsequent irrigation with distilled water. Root tips which 
were irrigated with sea water throughout the experiment served as 
controls. 
The application of distilled water causes a contraction of the 
protoplasm which often closely resembles the true plasmolysis 
produced by hypertonic sea water (which has been concentrated | 
by evaporation) or by hypertonic sugar solutions. Figs. 4 
and 5 show the appearance of such cells. The mode and the degree 
