THE BLOOD. 105 



ively. The same experimenter has, further, injected atmospheric 

 air into a loosened intestinal knot of a living dog, and analyzed the 

 air taken out after some time. He found a carbon-dioxide tension 

 of 1.1% of an atmosphere. The carbon-dioxide tension in the tissue 

 is strikingly greater than in venous blood, even if we use as basis 

 for our calculation the figures found by PFLUGER and his pupils, as 

 opposed to BOHR'S results of relatively high values, for the carbon- 

 dioxide tension. It is not disputed that the carbon dioxide simply 

 passes from the tissue to the blood according to the laws of 

 diffusion. 



V. The Quantitative Constitution of the Blood. 



The quantitative analysis of blood cannot be of value for the blood 

 as an entirety. We must ascertain on one side the relationship of 

 the plasma and blood-corpuscles to each other, and on the other side 

 the constitution of each of these two chief constituents. The diffi- 

 culties which stand in the way of such a task, especially in regard 

 to the living, non-coagulated blood, have not been removed. Since 

 the constitution of the blood may differ not only in different vas- 

 cular regions, but also in the same region under different circum- 

 stances, which renders also number of blood analyses necessary, it 

 can hardly appear remarkable that our knowledge of the con 

 stitution of the blood is still relatively limited. 



If any substance is found in the blood which belongs exclusively 

 to the plasma and does not occur in the blood-corpuscles, then the 

 amount of plasma contained in the blood may be calculated if we 

 determine the amount of this substance in 100 parts of the plasma 

 and serum, respectively, on one side and in 100 parts of the blood 

 on the other. If we represent the amount of this substance in the 

 plasma by p and in the blood by 5, then the amount x of the plasma 



in 100 parts of blood is x . 



P 



Such a substance, which occurs only in the plasma, is fibrin 

 according to HOPPE-SEYLER, sodium according to BUNGE (in cer- 

 tain kinds of blood), and sugar according to OTTO. The experi- 

 menters just named have tried to determine the amount of the 

 plasma and the blood-corpuscles, respectively, in different kinds 

 of blood, starting from the above-mentioned substances. 



