04 



other is a solid and fibrous substance, which, after being repeat- 

 edly washed, has the appearance of felt, the filaments of which cross 

 each other, are extensible and very elastic. This third part of the blood 

 is called fibrina^ it is very similar in its nature to muscular fibre, and like 

 it, gives out, on distillation, a considerable quantity of carbonate of am- 

 monia. Fibrina does not evist in the blood in a solid form, but in a state 

 of solution, and combined with the other constituent parts of the fluid, 

 as is indicated by the appropriate expression of liquid flesh (chair con- 

 lante) first used by Bordeu, in speaking of the blood. 



XCI. If the blood be exposed to the action of fire, if it be calcined and 

 reduced to powder, and if this pulverized substance be exposed to a 

 magnet, the presence of iron will be manifestly seen by the magnetic at- 

 traction. Authors do not agree in their accounts of the quantity of iron 

 contained in the blood. Menghini says, there is one part in the hundred ; 

 others, that it is in the proportion of 1 to 303$ so that it is probable, that 

 this constituent principle of the blood, like all the materials of our fluids, 

 may vary in quantity, according to different circumstances. 



Blumenbach justly observes, that iron is found only in calcined blood; 

 that none is to be found if it be slowly dried. This peculiarity is no 

 longer surprising, since Fourcroy has shown that iron existed in the 

 blood, in combination with the phosphoric acid, and formed with that 

 acid a phosphate of iron, with an excess of its base. - This salt becomes 

 decomposed by calcination, the iron is set free, and is acted upon by the 

 magnet. Physiologists attribute the colour of the blood to the presence 

 of the oxide of iron in that fluid. 



It has been the received opinion, that the red colour of the blood is 

 owing to the presence of phosphate of iron, which, being conveyed, of a 

 white colour into the blood, along with the chyle, meets with the pure 

 soda, by which it is dissolved, and from which it receives its colour; the 

 colour of the blood is, likewise, owing to the oxulizement of the metallic 

 portion, which is in very considerable quantity in that salt. This solu- 

 tion of the phosphate of iron by soda, the oxidizement of the excess of 

 iron, and the absorption of oxygen by albumen, constitute, in an especial 

 manner, hematosis or sanguification, which is principally carried on in the 

 lungs*. 



The respective proportion of the three parts into which the blood sepa- 

 rates spontaneously, varies considerably. The serum constitutes about 

 one half or three fourths of the fluid; the colouring matter and fibrina 

 are in inverse ratio of the serum, and it is observed, that the more bril- 



phosphates, does not acquire a red colour by this weak solution, -and that he has 

 neither detected iron nor lime in the entire blood, although both are so abundant in its 

 ashes. He therefore concludes, that the blood contains the elements only of the phos- 

 phate of iron, and of lime and magnesia, and of the carbonate of lime, united very dif- 

 ferently from their combination of these salts. Nor is it unlikely that these salts are 

 formed during incineration, from the presence of the elements of "their respective bases 

 in the blood, either in an uncombined, or in a differently combined form, the other 

 elements being partly furnished by this fluid also, and partly by the atmosphere, during 

 the incineration. Copland. 



* This opinion of FOURCROY respecting the source whence the blood acquires its red 

 colour, has, since his time, been adopted by some, and combated by other physiologists. 

 It is now entirely abandoned, because it i"s known that the colouring part of this fluid 

 may be obtained separately, and entirely exempt from iron. This colouring 1 portion of 

 the blood, according to M. VAUQ.UBLIX, does not change its colour when treated with 

 gallic acid a farther proof that it contains no iron. Copland. 



