1^2 Dr. Pearson on the colouring Matter 



a clear yellow liquid with abundance of black matter on its 

 surface. The separation of this coal-like matter is effected 

 most easily with this acid. 



It may not be quite superfluous to mention, that from the 

 bronchial glands, which were not at all coloured with black 

 matter, but were merely red, no black matter was separable 

 by the above mentioned acid, and alkaline solvents. 



I next examined the black and blue colouring substance of 

 the surface and Interior parts of the lungs. 



1. A portion of the lungs beautifully marked with a crowd 

 of these coloured areolae, spots, points, and lines, after being 

 washed till it no longer imparted a bloody tinge to water, 

 still retained these appearances undiminished. On pressure of 

 these coloured parts between the fingers, the skin was some- 

 times stained of a black colour. 



2. On treating the substance of the lungs, abounding in the 

 above described black and blue parts, in the same manner as 

 the bronchial glands just related, with water, with liquid caustic 

 potash, with muriatic and with nitric acids, similar phenomena, 

 with specially the separation of black matter, was observed. 

 The proportion, however, of . this black substance was very 

 much smaller to the animal matter dissolved, than in the former 

 cases. 



3. To shew that the black matter is of the same kind in the 

 differently figured black parts of the lungs, it may be worth 

 while to relate a particular experiment. 



A thin slice of about three inches square of the surface of 

 lungs exhibiting black lines, macular, and points under the 

 transparent pleura, was put into a vessel containing three 

 ounces measure of liquid nitric acid. On this it floated, but 



