PROTOPLASMIC CONTRACTIONS RESEMBLING PLAS- 
MOLYSIS WHICH ARE CAUSED BY PURE 
DISTILLED WATER 
W, J..V.-OSTERHOUT 
(WITH SIX FIGURES) 
True plasmolysis is produced only by solutions which are 
hypertonic, but appearances almost or. quite indistinguishable 
from it may be brought about by hypotonic solutions." Some 
light is thrown on the nature of this result by a study of certain 
cases in which it is caused by pure distilled water.’ 
Material for such study is afforded by marine plants. The 
root tips of the eel-grass (Zostera marina) are well adapted to this 
purpose. The roots were carefully removed from the sand in which 
they were growing and immediately placed in sea water. Some of 
the younger roots (which had not yet become brown at the end) 
were selected. About an inch of the root tip was removed and 
placed on a hollow-ground slide in such a way that the young root 
hairs did not come into contact with the glass. The root tip was 
covered with sea water and examined without a cover glass (by 
means of an 8 mm. objective and an ocular magnifying ten times). 
Root tips which were shown by such examination to be normal 
in appearance were fastened by means of vaseline to cover glasses 
which were then attached to irrigation chambers of the form shown 
in fig. 1. Care was taken to prevent the young root hairs from 
touching the glass or the vaseline. 
The arrangement of the apparatus may be understood from 
figs. 1 and 2. The irrigation chamber consists of an ordinary 
* Cf. Bot. Gaz. 46:53. sate 
* Water t ice distilled from glass i ll led as] ug samedi 
~~ o 
- ath. Pg sy Pe ., : i ey 
as any part of the apparatus is new. The water eed 1 in the ese experiments was pre- 
pared with due regard to these facts. In place of stoppers, plugs of absorbent cotton 
were used; contamination by spattering was prevented by baffling plates of glass and 
glass wool. The water so obtained was not toxic to such test objects as sensitive 
species of Spirogyra and the root hairs of Gypsophila. 
Botanical Gazette, vol. 55] [446 
