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Mycologia 



process was made slightly acid with sulphuric acid, and then 

 treated with a moderate excess of potassio-mercuric iodide solu- 

 tion. A yellowish amorphous precipitate formed at once, and 

 after heating the mixture for an hour on a water-bath, the pre- 

 cipitate was allowed to settle over night. Filtration through 

 double filters was often necessary to remove the colloidal precipi- 

 tate. The thoroughly washed precipitate was then suspended in 

 hot water and decomposed with hydrogen sulphide, while the mix- 

 ture was still hot. After this treatment the mercury sulphide 

 could be filtered off readily, especially if the mixture was first 

 allowed to stand on a steam-bath for an hour or more. The 

 filtrate contained some free hydriodic acid and also the compound 

 of the toxic substance with hydriodic acid. The careful addition 

 of silver sulphate, in the form of a saturated aqueous solution of 

 that substance, until no further precipitate was obtained, followed 

 by boiling for a short time, served to decompose and precipitate 

 all iodine derivatives. The yellow silver iodide was then filtered 

 off and the sulphuric acid in the filtrate removed by precipitation 

 with an excess of barium carbonate. The clear filtrate, from the 

 resultant barium sulphate plus the physical excess of barium car- 

 bonate, contained any alkaloidal substance that occurred in the 

 specimens under examination. We evaporated this aqueous solu- 

 tion to 10-15 c.c. on a water-bath and used small portions of it in 

 the pharmacological tests on frogs as indicated below. 



Thinking that cholin, resulting from the decomposition of 

 lecithins in the fungi, might be present with the toxic substance in 

 the final filtrates, we tested all of the latter for cholin. Rosen- 

 heim's* periodide test offers a beautiful and characteristic means 

 of detecting cholin. Practically all the extracts were found to 

 contain it. For the detection of cholin one adds a drop of plati- 

 num chloride solution to the liquid to be tested, which may be 

 only a few drops on a microscope slide. After allowing the water 

 to evaporate, the feathery and prismatic colorless crystals of the 

 cholin-platinum chloride and of the excess of platinum chloride 

 may be easily detected under the microscope. When these crystals 



* Rosenheim : New Tests for Choline in Physiological Fluids. Jour, of 

 Physiol. 1905, xxxiii, pp. 220-4. 



