206 PTOMAINES. 



They are further of considerable and increasing pathological interest and 

 that from two points of view. In the first place, as products of the 

 general putrefactive changes which animal tissues undergo, they may 

 account for the severe symptoms and not infrequent death which results 

 from the consumption as food of fish, sausages and tinned-meats. In 

 the second there appears to be increasing evidence of the formation of 

 special ptomaines by the organisms characteristic of specific diseases 

 so that the pathological conditions may be due rather to the products 

 formed by the organisms than to the organisms themselves directly, a 

 possibility of no small importance in the light of recent prophylactic 

 research. 



While the general reactions of the ptomaines place them as already 

 stated side by side with the vegetable alkaloids, their specific reactions 

 and properties exhibit considerable differences both in comparison with 

 each other and with those of the alkaloids J . Some are liquid and 

 highly volatile so that they pass off readily during distillation of their 

 aqueous solutions, others are liquid and non- volatile, others again solid 

 and crystalline. They exhibit equally marked differences in their 

 solubilities. Thus neither benzol nor petroleum-ether will extract them 

 from their acid aqueous solution. Ether on the other hand dissolves out 

 a few of the ptomaines from an acid solution and a large majority from 

 an alkaline solution. Some are more particularly soluble in chloro- 

 form, a few are insoluble in any of these reagents. Amyl-alcohol is the 

 one reagent in which as a class they appear to be almost generally 

 soluble (Brieger). Their behaviour with the usual alkaloidal precipi- 

 tants (mercuric and platinic chlorides, tannic acid, the double iodides 

 of potassium with mercury and other metals &c) is equally varied. 

 They are all precipitated by phospho-molybdic acid and most of them 

 yield crystalline compounds with a solution of iodine in hydriodic acid. 

 Possessed of an alkaline reaction they further act as powerful reducing 

 agents, many of them converting ferri- into ferrocyanides, the reduction 

 being evidenced by the formation of Prussian blue on the simultaneous 

 addition of ferric chloride. This property is however possessed by 

 many vegetable alkaloids and not by every ptomaine ; it cannot 

 therefore be regarded as a specific class-reaction for these substances 

 (Brieger, Gautier). Some of the ptomaines (Toxines) are extra- 

 ordinarily poisonous, producing effects which are frequently specific but 

 in many cases similar to those of certain vegetable alkaloids. Others 

 again are quite inert. 



The separation of the ptomaines, as of the vegetable alkaloids, 

 involves the application of methods (Stas-Otto's, Brieger's 2 ) which 



1 Otto, Anleit. ziir Ausmittelung d. Gifte. Aufl. 6, 1884, S. 88 et seq. 



2 Unters. iib. Ptomaine, n. 1885, S. 52. 



