1284 THE PTOMAINES. 



converted into the ethereal compound with indoxyl, when 

 skatole (synthetically prepared) is similarly employed a large 

 part reappears in the faeces ; and although at first the ethereal 

 sulphates are increased they subsequently diminish even with 

 continued injection of skatole and are stated to finally disap- 

 pear. Indoxyl-sulphuric acid may be regarded as a urinary 

 chromogen, since it yields a pigment, indigo, by oxidational 

 decomposition; so also may skatoxyl-sulphuric acid, but it is 

 found that the amount of pigment-forming material specifically 

 present in the urine of a dog fed with skatole is not so directly 

 proportional to the amount of skatoxyl-sulphuric acid as it is to 

 the similar compound of indoxyl when indole is administered. 

 It has been suggested that a large part of the skatolic chromo- 

 gen exists as a compound of skatoxyl and glycuronic acid. 

 When Jaffe's test (see p. 1282) for urinary indican is applied 

 to urine which contains skatoxyl compounds the results obtained 

 are as follows. The urine turns dark red or violet on the addi- 

 tion of hydrochloric acid, bright crimson on the addition of 

 nitric acid, and a similar colour is obtained if it is warmed 

 with hydrochloric acid and ferric chloride. The colouring 

 matter thus obtained is probably formed from the skatoxyl (not 

 known in the free state), and by reduction may be made to 

 yield skatole. 



Skatole has recently been described as occurring in a vegetable 

 tissue, namely, the wood of an East Indian tree, Celtis reticulosa. 



THE PTOMAINES. 



Although the substances to which the above name has been 

 given (from Trrcbfjia, a corpse) are now known to belong chiefly 

 to the class of compounds called amines, so that they provide 

 no chemical sequence to the bodies previously described, their 

 characteristic production during the putrefactive decomposition 

 of animal tissues seems to make this a suitable place for treating 

 of them. 



The ptomaines as a group may be said to closely resemble 

 the class of substances long known under the name of alkaloids 

 and obtained from plant tissues. The resemblance is shewn 

 not merely in their chemical constitution, but more obviously 

 in their similar solubilities in various fluids, in their general 

 behaviour towards reagents, and in some cases even in their 

 specific reactions, and more especially in their frequently pow- 

 erful (poisonous) action on the animal organism, the actions 

 of certain ptomaines being almost identical with those of cer- 

 tain vegetable alkaloids. The ptomaines may therefore be re- 

 garded as alkaloids of animal origin. The close similarity of 

 the two classes of substances has hence endowed the ptomaines 



