1893. NOTES AND COMMENTS. 247 



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. B3' 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 anaesthetics 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 



