CHEMISTRY OF THE PTOMAINES. 269 



alcohol. For further details in regard to this base see 

 page 265. 



Tyrotoxicox has been obtained in poisonous cheese 

 (Vaughan, Wallace, Wolff), in poisonous ice-cream 

 (Vaughan, Novy, Schbaree, Ladd), in poisonous 

 milk (Vaughan, Novy, Newton, Wallace, Firth, 

 Schearer), and in cream-puffs (Stanton). The methods 

 of separating this poison and its effect upon animals have 

 already been given with sufficient detail. Chemically, it is 

 very instable. When warmed with water to about 90°, it 

 decomposes. Hydrogen sulphide also decomposes it, there- 

 fore all attempts to isolate it by precipitation with some 

 base, such as mercury or lead, and then removing the base 

 with hydrogen sulphide, have failed. Its unstable char- 

 acter is illustrated by the fact that it may disappear 

 altogether within twenty-four hours from milk rich in (he 

 poison which is allowed to stand in an opeu beaker. 



With potassium hydrate it forms a compound which 

 agrees in crystalline form, chemical reactions, and the per 

 cent, of potassium which it contains, with the compound of 

 diazobenzole and potassium hydrate. This substance is best 

 obtained from milk containing tyrotoxicon as follows : The 

 filtered milk, which is acid in reaction, is neutralized with 

 sodium carbonate, agitated with an equal volume of ether, 

 allowed to stand in a stoppered glass cylinder for twenty- 

 four hours, the ether removed, and allowed to evaporate 

 spontaneously from an open dish. The aqueous residue is 

 acidified with nitric acid, then treated with an equal volume 

 of a saturated solution of potassium hydrate, and the whole 

 concentrated on the water-bath (this compQund is not 

 decomposed below 130°). On being heated the mixture 

 becomes yellowish-brown, and emits a peculiar aromatic 

 odor. On cooling the tyrotoxicon compound forms in 

 beautiful, six-sided plates along with the prisms of potas- 

 sium nitrate. 



With equal parts of sulphuric and carbolic acids, pure 

 tyrotoxicon gives a green coloration, but in whey the color 

 varies from yellow to orauge-red. This color reaction may 



