vn3, some other Animal FluiiJs, IftS 



tto»s which are ptculiar lo other varieties of colouring 

 matter 



These experimentG I sh^ll detail in the order in which 

 ihey v.ert' uiadc. 



1. Souie pure alumine was added to a concentrated 

 aqueous s ilution of the cilounng matter of the biood, and 

 alter twenty-four hours the niixiure, uhich had been fre- 

 quent! v agitated during thai period, was poured upon a 

 fiher, and the residuum wistied with hot distilled water. 



The tilirattd liquor had lost much of its original colour; 

 the akuniue had acquired a red tmge ; it was dried at a 

 temperature between 70° and 80 , during which it became 

 brown. 



2. Two hundred grains of alum were dissolved in four 

 fluid ounces oV a solution of the colouring matter, similar to 

 that €m played m the la-<t experiment. The colour of the 

 compound was bright red. Liquid ammonia was added, 

 and the precipitate collected, and earefully dried. It was 

 ot a dirty red, and after some davs exposure to light be- 

 canxe nearly brow n. 



From these, and o;her experiments which I have not 

 thought it necessary to detail, it appears that alumine will 

 not hirm a permanent red compound with the colouring 

 principle of the blood ; I was therefore next induced to 

 employ cxide of tin. 



3 JFiftv grains of crystallized muriate of tin (prepared 

 by lioiling tin fi'ir.gs in muriatic acid, and evaporating the 

 So ution.) were dissolved in four ounces of the solution of 

 colowritig matter, wh.ch immediately assumed a purple 

 tint, and became afterv^ ards brov\ n. It Aas diluted with 

 twice- us bulk o' wat-r. and put aside in a stopped phial. 

 On rximiiiing 11 three day* afterv\ards. a small quantity of 

 a bright red powder was observed at the bottom of the 

 phial, v\hich proved to consist of the colouring principle 

 combined with ihe metalhc oxide. A portion of this com- 

 pound which has been kept ni water for some weeks has 

 undergone no change of colour; but when dried by ex- 

 posure to air, it loses its brilhant tint, and becomes of a 

 dull red hue. 



To a compound solution of murine of tin and colouring 

 maltrr, similar to that employed in the last experiment, I 

 added a s.ifViciiiit quantity of solution ol potash to decom- 

 pose the bah ot 'in. The pncipilate thus obtained was 

 collected, and dried by exposure to the air of a warm room. 

 1% was uf a dull )red colour^ and has undergone no apparent 



change 



