30 CHEMICAL PHYSIOLOGY. 



blood. The muscles may either oxydise immediately 

 or store the oxygen in large quantities, particularly 

 during sleep, by means of their red colouring matter, 

 which is identical with hematocrystalline. Although 

 the carbonic acid affects the colour and condition of 

 the blood-corpuscles, nevertheless the latter are not 

 carriers of the carbonic acid. This gas is in the serum. 

 carbonic acid It is there partly dissolved in the same manner as in 



is in the * 



soda or Seltzer water, but to a great extent it is com- 

 bined with alkaline bases, particularly sodium. When 

 the blood-corpuscles of the venous blood arrive in the 

 lungs, they have undergone a change which consists in 

 the partial oxydation of a small quantity of their hema- 

 tocrystalline, and this is transformed into an acid 

 Hematic acid. w hich I will call hematic acid. This blood-acid contains 

 nitrogen. It is not similar to any of the acids we 

 know. It is not volatile but fixed : it is evolved from 

 the blood-corpuscles and passes into the serum at the 

 very moment when the former arrive in the small 

 breathing cells of the lungs. There the blood-acid 

 combines with the sodium, and the carbonic acid is set 

 free and is left to take its course, with water-vapour, 

 through the lung tissue into the respiratory passages.* 



* The excretion of carbonic acid from, the lungs is an act of specific 

 secretion, to which the presence of oxygen (and nitrogen) may be a 

 supplementary advantage (as favouring diffusion), but is not essential. 

 Hiiter's observation of twin foeti, which were born living within the 

 uninjured membranes and surrounded by the liquor amnii, and in that 

 condition exhaled gas, is to me conclusive evidence of this, as also of 

 my proposition that the act of first breathing is an act of secretion. 

 This theory is fertile of explanations of many dark phenomena, such as 

 the peculiar power of newborn children to sustain prolonged states of 

 asphyxia. 



