1893. NOTES AND COMMENTS. 24.7 
of the river. Sometimes it was embedded in laterite, and was then 
particularly appreciated on account of the peculiar red crust which 
enveloped a core of jade. The boulders were found by digging holes 
along the banks of the stream, or by diving to the bottom; but 
recently an enterprising Chinese has imported a diving-bell for the 
purpose. At the quarries at Tawmaw the mode of extraction is 
primitive and destructive. The surface of the rock is heated by large 
fires, and the cold at night is sufficient to crack it without pouring 
on water. By using crowbars and wedges in the cracks, large blocks 
of jade are obtained, which are broken with mallets to make them 
of a size suitable for transport. This rude treatment naturally 
damages the stone, and therefore the alluvial jade is greatly preferred. 
Jade, says Dr. Noetling, is a curious example of articles highly 
prized by certain people, and regarded with complete indifference 
by others. The Burmese and the Chinese, especially the latter, 
value a good piece of jade as much as, if not more than, so much 
gold. Thus, they will pay for a piece large enough for a signet-ring 
400 to 500 rupees, while the same piece sold in Europe will fetch little 
or nothing. ; 

ANESTHETICS AND PLANT TRANSPIRATION. 
In the February number of the Botanical Gazette Albert Schneider 
gives an account of experiments on the influence of anesthetics on 
plant transpiration. Jumelle concluded that sulphuric ether affected 
this function differently in the light and in the dark ; in the former it 
was increased, in the latter retarded. The increase in the light was 
supposed to be due to the action of the ether on the chlorophyll 
bodies, while the retardation in the dark was not explained. 
Verschaffelt, on the contrary, maintains that ether increases trans- 
piration both in the light and dark. Schneider claims that as these 
two experimenters used only parts of plants, their conclusions are 
of little practical value, the natural absorbent organ, the root, being 
absent. He himself uses small but entire plants of the potato, 
fuchsia, or geranium. Moreover, they may possibly have confounded 
evaporation with transpiration. The former—the mere passive loss of 
water—is much more rapid in the case of dead than living tissue, 
while the latter, the active giving up of water vapour, can only occur 
in living tissue, and is dependent upon protoplasmic activity. Pro- 
longed contact with ether may kill the leaves of the plant under 
_ experiment and the result be confused by substitution of evaporation 
for transpiration. 
Experiments on protoplasmic movements in the hair cells of 
Primula sinensis and other plants showed that ether vapour reduces 
their activity temporarily when exposed for a short time, and 
permanently if for a longer. 
Experiments with whole plants of the potato seemed to show 
conclusively that exposure to the vapour of ether, amyl nitrite, or 
