DESTRUCTIVE DISTILLATION OF ANIMAL MATTERS. 593 





Experiment. 

 23-25 





Calculation. 





Cai'bon, 



23-50 



C 16 



96 



Hydrogen, 



2-19 



2-44 



H 10 



10 



Nitrogen, 



. 



6-87 



N 2 



28 



Cadmium, 



. . . ... 



41-12 



Cd 3 



168 



Chlorine, 



• 



26-07 



Cl 3 



106-5 



100-00 408-5 



This agrees pretty closely with the formula 2 (C 8 H. N) + 3Cd CI. 



Products of the Decomposition of Pyrrol. 



The decompositions of pyrrol have not led to results as definite as might have 

 been anticipated ; and I have therefore restricted myself to the examination of 

 the red matter produced by the action of acids, and even that has been attended 

 with no little trouble and difficulty. 



Pyrrol Red. — This substance, as has already been frequently observed, is 

 produced whenever pyrrol is boiled with an excess of acid ; but notwithstanding 

 the apparently definite nature of the change, it is extremely difficult to obtain it of 

 uniform composition. This is due in part to its tendency to retain a small quantity 

 of acid, and in part also to the fact that continued boiling produces a farther 

 action, attended by the production of a dark colour in the acid liquid. When 

 this occurs, the red matter gives very variable results when analysed, and hence, 

 owing to the impossibility of ascertaining the exact length of time during which 

 the fluid should be boiled to insure complete formation of the red matter, with- 

 out going too far, the results of the analyses are by no means as concordant as 

 might be desired. After a good many trials, it was found that the most success- 

 ful results were obtained in the following manner : — Pyrrol was dissolved with 

 the aid of brisk agitation in sulphuric acid diluted with from four to six parts of 

 water, and the solution heated over the gas flame, while the flask was constantly 

 shaken. As soon as the red matter had separated in distinct flocks, it was thrown 

 on a filter and rapidly washed with boiling water, until the acid was almost 

 entirely removed, during which process the pyrrol red acquired a slightly brown 

 colour on the surface. A small quantity of diluted caustic potash was then 

 poured upon the filter, when the product immediately became of a fine orange 

 colour, which it retained after having been washed free of potash. 



Pyrrol red is a fine, light, porous substance, with an orange-red colour, which 

 becomes slightly brown by exposure to the air, especially when heated. It is in- 

 soluble in water, and is not readily moistened by that fluid. It is slightly soluble 

 in cold, more so in boiling alcohol ; and is again deposited on cooling in amor- 

 phous flocks. It is sparingly soluble in ether. Neither acids nor alkalies dissolve 

 it, but if boiled with them for some time it is decomposed. Nitric acid oxidizes 

 it, with the production of a resinous substance ; and if the action be continued for a 

 sufficient length of time, oxalic acid is found in the solution. When heated in 



