120 THE BLOOD. 



regarded by some as a necessity that there should be an organ 

 for the destruction of the corpuscles, and one for their forma- 

 tion. Regarding them, as we certainly must, as organized 

 bodies which are essential anatomical elements of the blood, 

 it is difficult to imagine what reasons, based on their function, 

 should lead physiologists to seek so persistently after an 

 organ for their destruction. The hypothesis that they are 

 used in the formation of pigment seems hardly sufficient to 

 account for this. 



In the present state of our science, the following seem to 

 be the most rational views with regard to the development 

 and nutrition of the blood-corpuscles : 



1. At their first appearance in the ovum, they are formed 

 by no special organs, for no special organs exist at that time, 

 but appear by genesis in the sanguineous blastema. 



2. When fully formed, they are regularly organized ana- 

 tomical elements, subject, to the same laws of gradual molec- 

 ular waste and repair as any of the tissues. 



3. They are generated de novo in the adult, when dimin- 

 ished in quantity by hemorrhage or otherwise, and under 

 these circumstances they are probably formed in the liquor 

 sanguinis by the same process by which they take their origin 

 in the ovum. 



Function of the Blood-Corpuscles. Though the fibrin 

 and albumen of the plasma of the blood are essential to 

 nutrition, the red corpuscles are the parts most immediately 

 necessary to life. We have already seen, in treating of trans- 

 fusion, that life may be restored to an animal in which the 

 functions have been suspended from hemorrhage, by the in- 

 troduction of fresh blood ; and while it is not necessary that 

 this blood should contain fibrin, it has been shown by the 

 experiments of Provost and Dumas and others, that the 

 introduction of serum, without the corpuscles, has no resto- 

 rative effect. When all the arteries leading to a part are 

 ligated, the tissues lose their properties of contractility, sen- 



