118 APPLIED BACTERIOLOGY 



obtained artificially by the oxidation of creatin. This base 

 is very poisonous in the case of guinea-pigs, causing total 

 paralysis. 



Tyrotoxicon. — This unstable body was first obtained by 

 Vaughan from poisonous cheese, and subsequently by 

 others in poisonous milk and ice-cream. It is decomposed 

 at a temperature of 90° C. It is described as crystallising 

 in needleSj which gradually decompose on exposure to moist 

 air. It has a ' dry ' taste and smells of stale cheese. Tyro- 

 toxin is not precipitated by the majority of the usual 

 alkaloidal reagents. In constitution Vaughan believes this 

 compound to be diazobenzene — potassoxide, CgHj.Ng.OK. 

 The symptoms produced by eating cheese or milk contain- 

 ing tyrotoxicon are vertigo, nausea, vomiting, cramps in the 

 legs, griping pains in the bowels attended by purging, 

 numbness, and great prostration. 



Vaughan found that three months are required for the 

 formation of tyrotoxicon in milk kept in tightly-stoppered 

 bottles, but that its formation was hastened by the presence 

 of the B. butyricus, tbe poison then being produced in 

 about ten days. This has been confirmed by Frith, who 

 found that if a piece of rancid butter were suspended in the 

 liquid, the poison can be detected in as little as five days. 



For the detection of tyrotoxicon in suspected milk, cheese 

 or ice-cream, Vaughan recommends the following process : 

 The curdled filtrate from the milk or ice-cream, or the 

 filtered cold water extract of the cheese, is neutralised with 

 sodium carbonate, transferred to a separator, and shaken 

 with its own volume of pure ether. The mixture is 

 allowed to stand for twenty-four hours, or until the ether 

 has separated, when it is allowed to evaporate spontaneously 

 in an open dish. The residue is dissolved in a little water, 

 and the liquid again shaken with ether, the ethereal liquid 

 again separated and allowed to evaporate spontaneously. 



