The Functions of the Blood: 87 



It is still doubtful whether the corpuscles consist of red 

 liquid, enclosed by a membrane, or whether they are semi- 

 solid, and of uniform structure throughout. Two of the latest 

 investigators, Max Schultze and Ofsiannikof, assert directly 

 opposite opinions upon this point. Whatever they be, how- 

 ever, it is at least certain that they possess a definite term of 

 life. They are incessantly being formed in the chyle and 

 lymph, and also probably in the liver and some other glands. 

 And after the completion of their work, they disappear or are 

 destroyed, this destruction being seen most remarkably in the 

 liver, and in the blood which has traversed muscular tissue.* 



The chief function of the blood-corpuscles in the body has 

 long been known, or, at any rate, strongly suspected. They 

 are the carriers of oxygen, the agents of oxidation, in the 

 animal body. During its passage through the lungs, the 

 blood, as every one knows, loses carbonic acid and takes up 

 oxygen. Every 100 volumes of the blood which enters the 

 lungs is capable, according to Claude Bernard, of absorbing 

 twenty-one volumes of oxygen. This is about seven times 'as 

 much as an equal quantity of water could dissolve, and 

 Berzelius, long ago, showed that serum, which differs but 

 slightly from liquor-sanguinis, was hardly superior to water in 

 this respect. Consequently, it is evident that the great mass 

 of the oxygen must be attracted by the blood-corpuscles. The 

 corpuscles, as before mentioned, constitute about one-half 

 of the bulk of the blood, and, therefore, allowing for the small 

 quantity dissolved by the liquor-sanguinis, we find that they 

 absorb thirty-nine per cent., or thirteen times as much oxygen 

 as water could. That this oxygen is combined in, and not 

 merely dissolved by, the corpuscles, is indicated by the fact 

 observed by Bernard, that pyrogallic acid, a substance that 

 combines eagerly with free oxygen, when it is injected into the 

 veins, will pass out of the body of the animal without under- 

 going oxidation. It has, therefore, been generally assumed, 

 although upon imperfect proof, that the colouring matter of 

 the corpuscles was capable of combining with oxygen in the 

 lungs, and afterwards of giving that oxygen out again — in 

 small doses, as it were — to the substances to be oxidized. 

 This notion has been recently raised to the dignity of a theory 

 by some beautiful experiments which physiology owes to a 

 physicist — Professor Stokes, of Cambridge. Stokes's re- 

 searches appear hardly to have received from physiologists the 

 attention they deserve, and I, therefore, venture to present a 

 brief description of them here. Hoppe-Seyler had previously 

 recorded the curious fact, that when a ray of white light passes 

 through a weak solution of blood, and is afterwards decom- 



* Bernard, "Liquides de rOrganisme," i. 460. 



