1896.] Anatomical and Physiological Researches. 31 
He considers the reduced transpiration as a guard against ex- 
cessive accumulation of salt. Stahl goes on with the work 
for non-halophytes where Schimper left it. He cultivated 
corn plants in normal solutions with and without 5 per cent. so- 
lution of cooking salt; also plantsin soil, some watered with the 
salt solution and others with well water. Inall cases he found 
that the plants given the salt solution stopped developing in 
a few days, while control plants kept on developing. It was 
found that there was no starch or sugar present in the plants 
watered with salt solution while it was plentiful in the others. 
In a few hours after watering with salt solution the stomata 
were closed, and the cobalt test showed very little evapora- 
tion, even in sunlight. When these plants with the stomata 
closed were exposed to an atmosphere containing several per 
cent. of CO, they were able to make starch. he presence 
of sodium chloride in any part of the plant may be demon- 
strated (according to Schimper) by the use of a saturated 
aqueous solution of thallium sulphate on tissues freed from 
air. Crystals of chlorothallium will appear in cells contain- 
ing the salt. The crystals are black by reflected light. In 
this way Stahl found that the sodium chloride passes into the 
epidermal cells but not into the guard cells of the stomata. 
This, of course, explains their closing. 
Leaves of Alisma Plantago, Menyanthes trifoliata, and 
Lilium candidum were allowed to absorb thallium sulphate 
(which does not cause the closing of the stomata for some 
time at least). After allowing transpiration to go on for some 
time, the chlorothallium was precipitated with calcium chlo- 
tide. It appears first and most strongly in the guard cells, 
showing, as Stahl thinks, that there is a current of water in 
this direction caused by the loss from the guard cells. Later 
the salt appears in the other epidermal cells also. 
Now in regard to the halophytes, it is well known that they 
thrive perfectly even with large amounts of salt in their tissues. 
he reason for this as far as the cells themselves are con- 
Shows, however, that these plants do lose large amounts of 
water and that all these arrangements for the reduction of 
transpiration are as far as possible to take the place of the 
lack of the power to close the stomata, so common in marsh 
