NATTJEAL HISTOET OV LAKE UEMI. 355 



concentration of the saline solution had become extreme, and the 

 salts were being deposited iipon the surface of the loathsome 

 black mud, reeking of sulphuretted hydrogen and probably 

 yielding marsh-gas as well, which seems to be such an inseparable 

 feature of salt lakes. For some distance from the water's edge 

 the foreshore was covered with a dazzling crust of white salt. 



The salt water has a very unpleasant physiological action upon 

 all the mucous membranes, and produces nausea if swallowed, 

 but is otherwise innocuous to the bather. The Syrians are in 

 the habit of bathing in the lake upon St. Thomas's day (July 3rd 

 O.S.), in order to commemorate the tradition that the Saint 

 crossed the lake on his way to India. On emerging from the 

 water the skin becomes rapidly covered with a thin crust of salt, 

 unless the water be rapidly removed with a towel. But although 

 harmless and even invigorating to man, the salinity is fatal 

 to any freshwater fish of the rivers which may happen to swim 

 out too far ; wherefore at the present day the lake forms a very 

 efficient barrier to the distribution of fish from one river to the 

 next. Quantities of dead fish may sometimes be seen near the 

 mouths of some of the rivers. I tried the experiment of putting 

 freshly-caught chub into the salt water, and found that they 

 died in three and a half minutes. "When the salt water was 

 gradually substituted for the fresh, the fish died when the 

 mixture contained about a third of the salt water, which was at 

 the end of forty minutes. On the 2nd of August a specimen 

 of the green tree-frog was found vainly endeavouring to escape 

 from the salt water into which he had accidentally jumped ; but 

 his rapidly weakening efforts showed that he too would soon 

 have become a victim of the salt water, and have involuntarily 

 verified Semper's observations (' Animal Life,' p. 150), had he 

 not succumbed to the collector's alcohol. 



FlanJcton. — It might very naturally have been supposed that 

 so hostile an environment as a siroug saline solution, surrounded 

 by a zone of a still stronger one almost saturated with sulphuretted 

 hydrogen, would have been incompatible with organic life. The 

 Lake of Urmi, however, is in no sense of the word a Dead Sea : 

 it is simply teeming with living organisms, both animal and 

 vegetable. Whether near the shore or miles from it, the clear 

 water may be seen to sparkle in the sunlight owing to the 

 enormous numbers of organisms which constitute its plankton. 

 Throughout all the vast volume of water the distribution of life 



