Dr. Meyer on the Gases of the Blood. 265 
of mercury can be read off by means of a divided millimetre 
scale. The instrument, of which a more minute description is 
given in the cited memoir, may also be employed for the deter- 
mination of the coefficients of absorption of other liquids which 
cannot be brought into contact with mercury. . Experiments 
conducted with the view of determining the degree of accuracy 
attainable with this arrangement gave satisfactory results, and 
are detailed in the original paper. 
For the purpose of determining the coefficient of absorption, 
I employed defibrinated blood, freed from all dissolved gases by 
ebullition in vacuo, at a temperature of about 30°. 
Absorptiometric experiments conducted with the blood thus 
prepared, showed that with the three gases, carbonic acid, oxygen 
and nitrogen, the quantity absorbed varied with the pressure to 
which the gas was subject ; and that the variation in the absorbed 
quantity is proportional to the increase or diminution of the 
pressure. The total amount of carbonic acid and oxygen taken 
up by the blood from a pure atmosphere of either of these gases, 
is, however, not proportional to the absolute pressure under 
which the absorption occurs. In other words, this total amount 
of dissolyed gas consists of two separate portions (as is the case 
in a solution of chlorine in water*), one of which is independent 
of the amount of pressure, whilst the other obeys Dalton and 
Henry’s law of absorption. The volume of gas dissolved by the 
volume of blood f, under the pressure P and at the temperature ¢, 
measured by the unit of pressure at 0° C., is 
A=kh+ahP; 
in which @ represents the coefficient of absorption, and & another 
constant, also dependent upon the pressure. 
In the case of nitrogen, on the other hand, the total quantity 
of absorbed gas is proportional to the pressure, so that the solu- 
tion appears to be purely a phenomenon of absorption. As, 
however, the quantity of nitrogen dissolved in the blood is very 
small, averaging about from 8 to 4 per cent. of the volume of 
blood employed, and as the errors of observation may possibly 
reach as high a limit as 1 per cent., the determination of the 
values of the absorption-coefficients could not be conducted with 
any great degree of accuracy according to the method described. 
The coefficient « for oxygen is likewise small, so that the 
amount of this gas absorbed proportionally to the pressure, does 
not lie much beyond the limit of experimentalerror. The value 
obtained for a at a temperature of 18° C. is 0-04 (see Exps. 19 
to 30 in the cited memoir). 
* Roscoe, “On the Absorption of Chlorine in Water,’ Quart. Journ. 
Chem, Soe. vol. viii. p. 14. 
