62 BACTERIAL POISONS. 



through the intestinal walls and form their poisonous pro- 

 ducts within the spleen and other organs. The fact that 

 NoVY found the bacteria in the spleen and liver of the 

 animals experimented upon confirms this view. 



Poisonous Milk. — In 1885 Vaughan found tyrotoxi- 

 con in mills which had stood in a well-stoppered bottle for 

 about six months. It was presumed that this milk was, 

 when first obtained, normal in composition, but since this 

 was not known with certainty, the following experiments 

 were made : Several gallon bottles were filled with normal 

 milk, tightly closed with glass stoppers, and allowed to 

 stand at the ordinary temperature of the room. From time 

 to time a bottle was opened and the test for tyrotoxicon was 

 made. These tests were followed by negative results until 

 about .three months after the experiment was begun. Then 

 the poison was obtained from one of the bottles. The coagu- 

 lated milk was filtered through paper. The filtrate, which 

 was colorless and decidedly acid in reaction, was rendered 

 feebly alkaline by the addition of potassium hydrate and 

 agitated with ether. After separation, the ethereal layer 

 was removed with a pipette, passed through a dry filter- 

 paper in order to remove a flocculent, white substance which 

 floated in it, and then allowed to evaporate spontaneously. 

 If necessary, this residue was dissolved in water and again 

 extracted with ether. As the ether takes up some water, 

 there is usually enough of the latter left after the sponta- 

 neous evaporation of the ether to hold the poison in solu- 

 tion, and in order to obtain the crystals this aqueous solu- 

 tion must be allowed to stand for some hours in vacuo 

 over sulphuric acid. 



From one-half gallon of the milk there was obtained 

 quite a concentrated aqueous solution of the poison after 

 the spontaneous ejraporation of the ether. Ten drops of 

 this solution placed in the mouth of a small dog, three 

 weeks old, caused within a few minutes frothing at the 

 mouth, retching, the vomiting of frothy fluid, muscular 

 spasms over the abdomen, and after some hours watery 

 stools. The next day the dog seemed to have partially 



