270 VENOMS 
the curious property of causing intense itching, pruritus, and even 
urticaria. This poison is perfectly soluble in alcohol, and can be 
prepared in the following manner :— 
The tentacles are cut off close to the body of the animal, and 
immersed for a few days in an equal weight of alcohol at 95° C. 
The red liquid that results is decanted, and then filtered. The 
insoluble material is compressed, and yields large quantities of fluid, 
which is filtered and mixed with the previous liquid. 
The whole is then evaporated in vacuo until there remains a 
thick oily liquid, which forms a red deposit. Filtration through 
paper is again employed, in order to separate this colouring matter, 
and to the filtered liquid is added an equal amount of alcohol at 
95° C. By this means there is precipitated a blackish, gummy 
matter, insoluble in alcohol. The remaining liquid is decanted 
and once more evaporated until it is reduced to a smaller volume 
than before. It is again treated with twice its volume of absolute 
alcohol, when it precipitates, in addition to salts and, gummy 
matter, a white flocculent substance, which is crude. thalassin. 
This can be purified by redissolving it in alcohol at a temperature 
of 98° C. On cooling it separates from the fluid in the form of 
crystals, which are placed on a filter and can then be redissolved in 
a small quantity of water. Absolute alcohol, added to this solution, 
precipitates the thalassin in the shape of very pure crystals, which 
contain 10 per cent. of azote, and melt at 200° C. 
This substance, in aqueous solutions, rapidly deteriorates owing 
to ammoniacal fermentation. When injected intravenously into 
dogs it produces pruritus, sneezing, and erythema, with intense 
congestion of the mucous membranes; 1 decigramme per kilo- 
gramme is a dose sufficient to produce these symptoms. It is not 
very toxic, since 1 centigramme is not lethal. 
One kilogramme of anemones is capable of furnishing about 
3 grammes of pure crystallised poison. 
In addition to thalassin, Richet succeeded in isolating from the 
tentacles of the same sea-anemones another poison insoluble in 
