22 CHEMICAL RESEARCHES 0N THE ANIMAL i'T.UIDS. 



The one portion was allowt-d to coagulate spontaneously ; the 

 otlierwas stirred lor half an hour with a piece of wood, so as 

 to collect the coagulnm, but to diffuse the principal part of 

 the colouring matter throuoh the serum. I'hese two portions 

 of coagulum were now dried in a water-bath, and equal 

 iveights of each reduced in a platina crucible to the state of 

 coal, which afterward was incinerated. The ashes were di- 

 gested in dilute nitromuriatic acid, and the solution satu- 

 rated with liquid ammonia, in order to precipitate the phos- 

 phate of lime, as well as any iron which might have been 

 present. 



The precipitates were collected, dried, and treated with 

 dilute acetic acid, by which they were almost entirely dis« 

 solved ; some very minute traces only of red oxide of iron 

 remaining, the quantity of which was similar in both casesj 

 and so small as nearly to have escaped observation. 

 It appeared It is reasonable to infer, that, if the colouring matter of 



"°'* the blood were constituted by iron in any state of com- 



bination, a larger relative proportion of this metal would 

 have been discoverable in the former than in the latter coa- 

 gulum ; but frequent repetitions of these experiments have 

 shown, that this is not the case, and the followiiig result ap- 

 pears to complete the evidence on this subject. 

 This farther The colouring matter of 4 pint of blood was diffused by 

 connrmed. agitation through the serum, from which it was allowed 

 gradually to subside, the coagulum having been removed : 

 ^ after twenty-four hours, the clear serum was decanted off, 

 and the remainder containing the colouring matter, aftef 

 having been evaporated to dryness, was incinerated, and the 

 ashes examined as in former experiments. But the traces of 

 iron were here as indistinct as in the other instances above 

 mentioned, although a considerable quantity of the colouring 

 matter had been employed. 



The minutife of analysis I have purposely excluded, as 

 leading into details which would exceed the proper limits of 

 this paper, and unnecessary in the present investigation ; I 

 shall now merely dwell on the principal results which have 

 been obtained, and on the general conclusions which these 

 afford, 



^To be coyichded in our next. J 



V. 



