CHEMICAL BASIS OF THE ANIMAL BODY. 1285 



with very considerable interest from a medico-legal point of 

 view in virtue of the not infrequent use of the vegetable 

 alkaloids for criminal purposes and the now obvious possibility 

 that the detection of alkaloids in the corpse may afford no reli- 

 able information as to the administration of the same during 

 life. They are further of considerable and increasing patho- 

 logical 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 symp- 

 toms and not infrequent death which results from the consump- 

 tion 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 differ- 

 ences both in comparison with each other and with those of the 

 alkaloids. 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 crys- 

 talline. They exhibit equally marked differences in their 

 solubilities. Thus neither benzene nor petroleum-ether will 

 extract them from their acid aqueous solution. Ether on the 

 other hand dissolves out a few of the ptomaines from fin acid 

 solution and a large majority from an alkaline solution. Some 

 are more particularly soluble in chloroform, 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. 

 Their behaviour with the usual alkaloidal precipitants (mer- 

 curic and platinic chlorides, tannic acid, the double iodides of 

 potassium with mercury and other metals, etc.) is equally 

 varied. They are all precipitated by phospho-molybdic acid 

 and most of them }ueld 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 evi- 

 denced 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. Some of the ptomaines (toxines) are extraordina- 

 rily poisonous, producing effects which are frequently specific 

 but in many cases similar to those of certain vegetable alka- 

 loids. Others again are quite inert. 



