COLLIDIN ISOMER. 255 



able, somewhat nauseating odor. Treated with potash it yields a 

 colorless, aromatic, very alkaline oil. 



The base on oxidation with boiling potassium permanganate yields 

 an acid, CyH^NOj, and from this fact the discoverers conclude that 

 the base is a dihydro-dimethylpiridin, CjH^(CH3)2NH. 



It is moderately poisonous. In small doses it diminishes the gen- 

 eral sensibility ; in larger doses it produces trembling, especially of 

 the head ; profound depression alternating with periods of extreme 

 excitement ; paralysis of the posterior limbs, and death. 



A Base, CjHjjN, isomeric but not identical with aldehyde coUidin, 

 was obtained by Nencki as early as 1876, by allowing a mixture of 

 200 grams of pancreas and 600 grams of gelatin in ten liters of 

 water to putrefy for five days at 40°. The method used by Nencki 

 for its isolation is as follows i The fluid mass was distilled with sul- 

 phuric acid, to drive off the volatile acids, then rendered alkaline 

 with barium hydrate, and again distilled. The distillate was re- 

 ceived in dilute hydrochloric acid, and on evaporation gave a crys- 

 talline residue of ammonium chlorid, and of a salt which formed 

 long rhombic plates. The latter were separated from the ammonium 

 salt by absolute alcohol. The free base was obtained from the salt 

 by treating it with sodium hydrate, and extracting the solution with 

 ether. 



This compound, as already stated, is isomeric with coUidin, and 

 also with O. de Coninck's base, with which it is possibly identical. 

 The latter, however, will be described separately. 



On decomposing fibrin by means of streptococci Emmerling (1897) 

 obtained besides leuein, tyrosin and various organic acids, methyl- 

 amin, tri-methylamiu and a base, CjII,jN, which apparently differed 

 from that of Nencki and that of Gautier and Etard by the ready 

 solubility of its platinum salt. It had no effect on guinea-pigs. It 

 formed a syrupy liquid, and gave with gold chlorid a yellow precipitate 

 which rapidly became reduced. Platinum chlorid gave no precipi- 

 tate but the mixture on slow evaporation gave yellowish-red crystals 

 of the platinochlorid. Concentrated solutions gave a picrate which 

 melted at 172°-175°. Owing to the slight pyridin odor of the base 

 the latter was regarded as a propyl pyridin. 



The free base is oily in character, and possesses a peculiar, not 

 unpleasant odor. It readily absorbs carbonic acid gas from the air, 

 forming after a time a lamellar, crystalline mass of the carbonate. 

 The salt of this base on heating gives off an oil which burns with a 

 smoky flame, and possesses an odor similar to that of xylol or cumol. 

 Nencki was therefore at first of the opinion that the ptomain was an 

 aromatic base, probably an isophenyl-ethylamin of the following 



composition: CjHj— CH<' ^t/- He supposed that it was formed 



