558 [May 7, 



2nd. They were then submitted to distillation in a glass retort the 

 distilled products being saved in three or four separate portions by 

 changing the receiver at different stages of the process. In this way 

 the presence of nitrobenzole was discovered. 



3rd. The residue in the retort, when reduced to a pulpy mass by 

 the distillation, was treated with strong spirit of wine and filtered. 



4th. The filtered alcoholic solution which contained the aniline 

 was treated with a slight excess of subacetate of lead, and again 

 filtered. In this way gum, dextrine, &c. were removed. 



5th. The filtered solution was treated with a slight excess of a 

 saturated solution of sulphate of soda in water. In this manner the 

 excess of lead was precipitated as a sulphate. 



6th. The clear solution was then made very alkaline with caustic 

 potash, and distilled to dryness from an oil-bath. The aniline, to- 

 gether with ammonia from the animal matters, was found in the clear, 

 colourless, distilled spirit. 



7th. This was neutralized, or rather made acid, with a slight excess 

 of dilute sulphuric acid, and evaporated nearly to dryness in a white 

 porcelain dish. If necessary, the spirit was saved by distillation. 



8th. The residue was of a pinkish colour if aniline was present, 

 and occasionally there were little streaks of blue around the edges of 

 the white porcelain dish. If the quantity of the saline residue was 

 not more than a grain or so, it was at once tested by dissolving it in 

 a few drops, or even in a single drop, of dilute sulphuric acid (1 to 1). 

 A small portion of it was then placed upon a strip of bright platinum ; 

 and the platinum having been connected with the positive pole of a 

 single cell of a Grove's battery, the liquid was touched with the ne- 

 gative pole : in a few seconds, if aniline was present, the liquid would 

 acquire a bronze, a blue, or a pink colour ; the kind of colour being 

 dependent on the am ount of aniline present bronze being the result 

 of much aniline, and pink of a very little. In this way at least the 

 SoVo^h part of a grain of aniline was easily recognized. 



To another portion of the acid liquid placed upon a white porcelain 

 plate, a little peroxide of lead or red prussiate of potash was added, 

 and a blue or purple reaction followed. This test is not so delicate 

 as the last, for it fails when the amount of aniline is less than the 

 yeVoth of a grain. 



Other tests may be resorted to if necessary, as when the quantity 



