270 BACTERIAL POISONS. 



be used as a preliminary test in examining milk for tyro- 

 toxicon. It is best carried out as follows : Place on a clean 

 porcelain surface two or three drops each of pure carbolic 

 and sulphuric acids. Then add a few drops of the aqueous 

 solution of the residue left after the spontaneous evapora- 

 tion of the ether. If tyrotoxicou be present, a yellow to 

 orange-red coloration will be produced. This test is to 

 be regarded only as a preliminary one, for the coloration 

 may be due to the presence of a nitrate or nitrite, or as 

 HUSTON has shown, to butyric acid. The tyrotoxicon 

 must be converted into the potassium compound and puri- 

 fied before the absence of nitrate or nitrite can be positively 

 demonstrated. Moreover, the physiological test should 

 always be made in testing for this poison. 



With platinum chloride in alcoholic solution tyrotoxicon 

 forms a compound which explodes with great violence at 

 the temperature of the water-bath. This also corresponds 

 with the compound of platinum chloride and diaxobenzole. 



Pure tyrotoxicon is insoluble in ether, and its extraction 

 from alkaline solutions by this solvent is due to the pres- 

 ence of foreign matter, with which the poison is taken up 

 by the ether. 



The physiological action of this ptomaine has been suf- 

 ficiently discussed in a preceding chapter. 



MYDALEINE (/wfa/^of, putrid) is a poisonous base ob- 

 tained in 1885 from putrefying cadaveric organs, liver, 

 spleen, etc. (BuiEGEii, II., 31, 48). Though it is appa- 

 rently present on about the seventh day, it is unobtainable 

 until about the third or fourth week. The method for its 

 separation from the accompanying bases is given under 

 Sapriue (page 220). It is liable to occur in the mercuric 

 chloride filtrate, as well as in the precipitate, inasmuch as 

 the double salt is insoluble only in perfectly absolute alco- 

 hol. In order to purify the platinochloride obtained as on 

 page 221, it is repeatedly rcerystalli/ed from a very small 

 quantity of lukewarm water. This base has not been ob- 

 tained in sufficient quantity to permit of a complete deter- 

 mination of its composition. It is probably a diamine, 



