106 



liable to crufh the animal as a blow from a hammer), and 

 with a needle laid open the vein, which was found to contain 

 a tenaceous yellowifli matter, of the colour and confiftence 

 of thick cream; after which a fine pointed, fiiff hair-pencil 

 was introduced, and feveral marks were made upon linen, 

 filk, and paper. As foon as the fluid was expofed to the 

 air it became of a brighter yellow, and fpeedily turned to 

 a pale green on the feveral materials, and continued to 

 change imperceptibly darker, until it had obtained a bluifli 

 caft, and from that to a purplifli-red, more or lefs deep ac- 

 cording to the quantity ufed ; and thefe changes were more 

 or lefs accelerated by the prefence or abfenceofthefolar 

 rays; but even without the influence of the fun, it went 

 through all the changes in the courfe of two or three hours. 



A portion of the fluid mixed with diluted vitriolic acid, did 

 not at firft appear to have been fenfibly affedhed, but by more 

 antimately mixing it in the fun, it became of a pale purple, 

 or purplifli-red, without any of the intermediate changes. 



Several marks were now made on finecalico, in orderto 

 try if it was poflible to difcharge the colour by fuch chemical 

 means as were at hand ; and it was found that after the co- 

 lour was fixed at its laft natural change, 7iitroiis, no more 

 than vitriolic acid, had any other effeil than that of rather 

 brightening it; aquaRegia with, and without folution of tin, 

 and Marine acid, produced no change ; nor had fixed, or 

 volatile alkali any lenfible effedt. It does not in the leal^ give 

 out its colour to alcohol like cocliincal, and x\\eJuccuso{ the 



animal. 



