808 CHEMISTRY OF RESPIRATION. 



tity of alkali. This follows from the analyses of PFLUGER. He found 

 19 per cent carbon dioxide removable by the air-pump and 54 per cent 

 firmly combined carbon dioxide in a strongly alkaline bile, but, on the 

 contrary, 6.6 per cent carbon dioxide removable by the air-pump and 

 0.8 per cent firmly combined carbon dioxide in a neutral bile. Alkaline 

 saliva is also very rich in carbon dioxide. As average for two analyses 

 made by PFLUGER of the submaxillary saliva of a dog we have 27.5 per 

 cent carbon dioxide removable by the air-pump and 47.4 per cent chem- 

 ically combined carbon dioxide, making a total of 74.9 per cent. KULZ l 

 found a maximum of 65.78 per cent carbon dioxide for the parotid saliva, 

 of which 3.31 per cent was removable by the air-pump and 62.7 per 

 cent was firmly combined. From these and other reports as to the 

 quantity of carbon dioxide removable by the air-pump and chemically 

 combined in the alkaline secretions it follows that bodies occur in them, 

 although not in appreciable quantities, which are analogous to the pro- 

 tein bodies of the blood-serum and which act like weak acids. 



The acid or at any rate non-alkaline secretions, urine and milk, con- 

 tain, on the -contrary, considerably less carbon dioxide, which is almost 

 all removable by the air-pump, and a part seems to be loosely combined 

 with the sodium phosphate. The figures found by PFLUGER foi the 

 total quantity of carbon dioxide in milk and urine are 10 and 18.1-19.7 

 per cent respectively. 



EWALD 2 made investigations on the quantity of gas in pathological 

 transudates. He found only traces, or at least only very insignificant 

 quantities of oxygen in these fluids. The quantity of nitrogen was about 

 the same as in blood; that of carbon dioxide was greater than in the 

 lymph (of dogs), and in certain cases even greater than in the blood after 

 asphyxiation (dog's blood). The tension of the carbon dioxide was 

 greater than in venous blood. In exudates the quantity of carbon 

 dioxide, especially that firmly combined, increases with the age of the 

 fluid, while, on the contrary, the total quantity of carbon dioxide, and 

 especially the quantity firmly combined, decreases with the quantity 

 of pus-corpuscles. 



II. THE EXCHANGE OF GAS BETWEEN THE BLOOD, ON THE ONE HAND, 

 AND PULMONARY AIR AND THE TISSUES, ON THE OTHER. 



In the introduction (Chapter I, p. 3) it was stated that we are to-day 

 of the opinion, derived especially from the researches of PFLUGER and 

 his pupils, that the oxidations of the animal body do not take place in 

 the fluids and juices, but are connected with the form-elements and 



1 Pfliiger, Pfliiger's Arch., 1 and 2; Kiilz, Zeitschr. f. Biologie 23. It seems as if Kiilz's 

 results were not calculated at 760 millimeters Hg, but rather at 1 meter. 



2 C. A. Ewald, Arch. f. (Anat. u.) Physiol., 1873 and 1876. 



