VENOMS IN THE ANIMAL SERIES 271 



alcohol at 50' C, and richer in azote (14 per cent.), to which 

 he has given the name congestin. This is not destroyed by 

 heating to 107 C. It is prepared by precipitating, by four times 

 its volume of alcohol, a solution of anemone-tentacles in 5 per 

 cent, fluoride of sodium. The solid matter, after being precipi- 

 tated and dried, is redissolved in six times its volume of water, 

 and then filtered. On adding to the filtered and fluorescent 

 liquid its volume of alcohol at 90' C, the congestin. is precipi- 

 tated. It is purified by redissolving it in water, and freeing it 

 by dialysis from the fluoride of sodium that it has retained. In 

 this way there is obtained, after evaporation, a product sufficiently 

 toxic to kill dogs in twenty-four hours in a dose of 2 milligrammes 

 per kilogramme. 



Congestin exerts a sensitising or anaphylactic effect upon 

 animals as regards thalassin, and is lethal in a dose of about 

 •5 milligrammes per kilogramme of animal, and sometimes even 

 in a dose of 7 decimilligrammes. It is therefore a very active 

 poison. 



Dogs, on the other hand, into which is injected first thalassin, 

 and then, some time afterwards, congestin, are perfectly resistant 

 to inoculation by the latter. Thalassin is therefore antitoxic or 

 antagonistic to congestin. 



The latter, on the contrary, if injected first of all in non-lethal 

 doses, renders animals so sensitive to inoculation with thalassin, 

 that from 4 to 5 milligrammes are sufficient to cause death. 



The tentacles of these anemones therefore contain two toxic 

 substances antagonistic to each other, which can easily be separated, 

 since one {thalassin) is soluble in concentrated alcohol, while the 

 other is completely insoluble in this reagent. 



These poisons are not only extremely interesting from a physio- 

 logical point of view, but also possess a practical interest, since it 

 is at the present time almost a matter of certainty that they are 

 the cause of a malady which specially affects sponge-divers in the 

 Mediterranean. 



