SEPARATION OF THE PTOMAINES 121 



crystallisation begins to take place. All the inorganic 

 salts crystallise out first; these are removed, and (a) in 

 case of the solid ptomaines the mother - liquid further 

 evaporated, when needle-like crystals are thrown out of 

 solution. These may be dissolved in water, but they are 

 insoluble in absolute alcohol, ether, benzine, and chloroform. 

 The substances so yielded, the ptomaines, may be pre- 

 cipitated by the salts, particularly the chlorides, of the 

 heavy metals, (b) In the case of the liquid ptomaines the 

 mother - liquid is rendered faintly alkaline, the ptomaine 

 extracted with a suitable solvent and separated. This is 

 then evaporated in vacuo, when the base is obtained in a 

 free condition. 



The Stas-Otto process,* such as is used for the extrac- 

 tion of strychnine, may also be used for the extraction of 

 ptomaines from animal matters. 



Great care should be taken to use perfectly pure reagents 

 in any work connected with the extraction of ptomaines. 

 Ether and amylic alcohol are very liable to contain traces 

 of pyridine and other bases, which are liable to be mis- 

 taken for ptomaines. 



Toxalbumoses, Bacterial Proteins, etc. — As has already been 

 stated, many of the pathogenic bacteria produce a number 

 of intensely poisonous bodies which are allied in their con- 

 stitution and characters to albumins or proteids. 



Loffler, in 1887, when examining the products of pure 

 cultures of the diphtheria bacillus, found that if a broth 

 culture was freed from the bacilli by filtration through a 

 porcelain filter, and was then injected into a guinea-pig, it 

 gave rise to the same local reaction and paralytic symptoms 

 as when the bacilli themselves were inoculated. 



* For a description of this somewhat lengthy process, and also a 

 further account of the chemistry of the ptomaines, see Allen's ' Com- 

 mercial Organic Analysis,' vol. iii., parts ii. and iii. 



