Destructive Distillation of Animal Substances. 147 



required by theory for the higher base. Being convinced that 

 the separation of two bases approximating so closely in their boil- 

 ing-points as aniline and the substance I expected to find, could 

 not be effected by fractionated distillation, or at least only by an 

 expenditure of time, labour and material, altogether out of pro- 

 portion to the importance of the object to be attained, I endea- 

 voured to accomplish it by crystallization. Having observed 

 that the other members of the picoline series gave highly soluble 

 and even deliquescent oxalates, I conceived that by converting 

 the mixed bases into salts of that acid, it would be easy to sepa- 

 rate the rather sparingly soluble and highly crystallizable oxalate 

 of aniline, and obtain the oxalate of the other base in a state of 

 purity. But this expectation was not confirmed by experiment ; 

 for neither from the portion boiling about 340°, nor even from 

 that collected at 360°, and corresponding therefore with the 

 boiling-point of pure aniline, could the slightest trace of crystal- 

 lized oxalate of aniline be obtained, although both fractions gave 

 the reaction of that base in the most powerful manner. The 

 experiment was varied in every possible way by the use of water, 

 spirit, and absolute alcohol, but by allowing these fluids to eva- 

 porate spontaneously only a thick syrup was obtained, without 

 the slightest indication of crystallization. Even the addition of 

 aether to its alcoholic solution gave only a syrupy fluid, and no 

 crystals ; and I was forced to conclude, that, even in the portion 

 of the mixed bases corresponding to the boiling-point of aniline, 

 its quantity was so small in proportion to the other substances, 

 that the properties of its salts were entirely masked by them. 



Not succeeding in obtaining the pure aniline, and so separa- 

 ting it from the other base, the question came to be, how to get 

 rid of the former substance in the best possible way. For this 

 purpose I availed myself of the extreme stability of the bases of 

 the picoline series mentioned in my former paper, which is so 

 great that they resist even the action of strong nitric acid, by 

 which aniline is entirely destroyed. When the base, boiling 

 between 340° and 345°, is mixed rapidly and in large quantity 

 with nitric acid, much heat is evolved, and a brisk action takes 

 place ; and if the portion boiling about 360° is employed, the 

 action is so violent as to be almost explosive, and it is requisite 

 to add the base drop by drop to the acid, which must be kept 

 carefully cool. The acid fluid acquires a deep red colour, and 

 on boiling, red fumes are abundantly evolved, accompanied by 

 an odour resembling that of bitter almonds. After the action 

 has ceased, the fluid becomes muddy when mixed with water, 

 and a thick reddish-yellow oil is deposited, which has exactly the 

 odour of nitrobenzide, and resembles it in many of its properties. 

 The quantity of this substance produced is by no means large, 



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