THE BLOOD. 129 



The salts contained in the serum (and consequently in 

 the liquor) are not identical with those which we have de- 

 scribed as found in the globules. The salts contained in the 

 blood form 8 or 10 in 1000 parts, the principal portion being 

 of an alkaline character. Soda, especially in the form of car- 

 bonate, is the basis of most of the salts in the liquor. The 

 serum is extremely alkaline, and the necessity of this reaction 

 is plain, if we remember all the reductions to be made in this 

 liquid. There are, besides, few metals whose presence has 

 not been suspected in the blood (liquor and cruor) ; iron and 

 manganese have been found in it, and occasionally copper, 

 which we might, perhaps, consider a normal constituent. It 

 is also asserted that arsenic has been discovered ; lead rarely : 

 these are, however, simply chemical curiosities. (These last- 

 named substances exist in such minute quantities that we 

 might leave them out of consideration. Am. ed.) 



Gases of the Blood. Blood contains not only solids 

 and liquids, but gases also. Considered in regard to respira- 

 tion the blood is really a solution of gas. 1. We have 

 already seen that the red globule is the medium of a certain 

 quantity of oxygen. A smaller proportion of the same gas 

 is dissolved in the liquor. 2. The carbonic acid is contained 

 wholly in the serum, partly in a state of solution, partly 

 combined with the alkaline carbonates, which thus pass into 

 the state of bi-carbonates (Emile Fernet). 1 We shall study 

 the gases of the blood more fully when we come to the sub- 

 ject of respiration, and we shall thus discover that the blood 

 is the essential vehicle of those gases, which supply the com- 

 bustion of the tissues or may be the result of combustion. 



The question of the albuminoid substances of the blood is one 

 of those which have been the most studied, and yet is far from 

 being completely elucidated. It is now proved that the fibrine is 

 not produced in the globules, as was formerly believed, and that it 

 does not represent a substance dissolved in the blood, either by the 

 action of chloride of sodium or of ammonia (Richardson), though 

 the liquefying action of these substances is undeniable. Robin 

 and Verdeil had already demonstrated (1851) that fibrine does not 

 pre-exist in the blood as a concrete substance, but naturally is in a 

 liquid state, and generally only ceases to be so when taken from 

 the system. Now, however, we go further, and recent researches, 

 which are still incomplete, lead us to look upon it as the result of 



1 Emile Fernet, " Du Role des Principaux Elements du Sang 

 dans P Absorption ou le Degagement des Gaz de la Respiration." 

 Paris, 1858, in 4to. 



9 



