278 Dr, Prevost and M. Dumas on [Oct. 



not appear to differ at all from fibrin. The action of acids upon 

 albumen leads to the same conclusion, although there are two dif- 

 ferent operations to be distinguished ; first, the saturation of the 

 soda; secondly, the action of the acid upon the albumen. The 

 first explains the precipitation of albumen by the greater number 

 of acids, the action of the acids depending upon their nature ; 

 thus acetic and phosphoric acids redissolve, or at least reduce, 

 even fibrin itself to a gelatinous state, and consequently they do 

 not precipitate it from its alkaline solutions. 



MM. Prevost and Dumas observe, that the history of the 

 colouring matter of the blood would have been long since set- 

 tled, if it had not been for an error caused by a very simple cir- 

 cumstance : the colouring matter of the blood, owing to its 

 extreme divisibility when putinto water, and to its passing through 

 filters, has been supposed to be soluble in water. By the aid of 

 a microscope, however, the particles are perceptible, and by 

 standing, they separate in the state of a dense red substance. On 

 this account the authors conceive that the action of reagents 

 upon the colouring matter of the blood has never been satis- 

 factory. 



The colouring matter of the blood appears to be formed of an 

 animal substance in combination with peroxide of iron. Expe- 

 riments hitherto made would lead to the conclusion that it is 

 albumen ; but as chemists have always operated upon a mixture 

 of red matter, white globules, and the albumen of the serum, the 

 question is undecided, and the authors expressly state their 

 belief, that the processes proposed by MM. Berzelius, Brande, 

 and Vauquelin, to isolate the colouring matter, are all fallacious. 



MM. Prevost and Dumas observe, that it is much more easy 

 than it has been supposed, to determine the proportions of the 

 different animal matters which the blood contains, and the fol- 

 lowing are the results of their experiments : — 



MammiferiB. 



Green monkey (Callitriche), Blood drawn from the basilica. 



Serum. Blood. 



Water 908 Water 7760 



Albumen and salts .... 92 Particles 1461 



■ Albumen arid salts . . . 779 



1000 



10000 

 Man in a healthy state : venous blood : mean of many analyses. 



Serum. Blood. 



Water 900 Water 7839 



Albumen and salts .... 100 Particles 1292 



— Albumen and salts . . . 869 



10000 



1000 



