180 CHEMICAL RESEARCHES ON THE ANIMAL FLUIDS* 



louring matter its coagulation 3 the fibrina is thus removed, and the colouring 

 "^^' matter diffused throug^li the serum, from which it gradually 

 subsides, being difficultly soluble in that fluid ; on decanting 

 off the supernatant serum, the colouring matter remains in a 

 very concentrated form. When other modes of procuring it 

 were employed, they will be particularly mentioned j but as I 

 have not found the serum which is retained interfere much 

 with the effects of various agents upon the colouring principle/ 

 the method just noticed was commonly adopted. 



It appears to ^- When the colouring matter thus collected is microsco* 



consist of glo- picaliy examined, it seems, as Lewenboeck first observed'^, 

 buies 



' to consist of minute globules. These are usually described ae 



not soluble in soluble in water, a circumstance which ray own observations 

 water, led me to doubt, and which the more accurate experiments of 



Dr. Young, an account of which, intended for publication, he 

 has kindly permitted me to peruse, have completely disproved, 

 though the 3. The effect of water upon the red globules is to dissolve 



princb"^i their colouring matter, the globule itself remaining colourless, 

 them is. and, according to Dr. Young, floating upon the surface. 



The aqueous "^^'^ aqueous solution is of a bright red colour, and not very 

 solution de- prone to putrefaction. When heated, it remains unaltered at 

 composed by temperatures below 190° or 200"^ Fahrenheit ; at higher tem- 

 peratures it becomes turbid, and deposits a pale brown sedi- 

 ment : if in this state it be poured upon a filter, the water 

 passes through without colour, so that exposure to heat not 

 only destroys the red tint, but renders the colouring matter 

 insoluble in water, 

 alcohol and Alcohol and sulphuric ether added to this solution also ren- 



et.her. der it turbid, and when these mixtures were filtrated, a colour- 



less and transparent liquor was obtained. 

 Th« precipl- 4, The matter remaining upon the filter was insoluble in 

 tate partly so- water, in alcohol, and in sulphuric ether 3 but when digested 

 iuble in acids. . ,., . . . , 1 • -j ,- ..1 



m dilute muriatic or sulphuric acid, a portion was taken up 



forming a brown solution. I regard this soluble portion as a 

 modification of the colouring matter produced by the opera- 

 tion of heat : the insoluble, residuum had the properties of 



albumen. 



* Halter, Elem. Pliysiulog. Vol. 1, p. 51. 



Ejects 



