ANALYSIS OF THE BLOOD FOR GASES. 463 



Bernard's experiments were made chiefly on dogs, and 

 had especial reference to the proportion of oxygen in the 



rarefaction of the air was not carried sufficiently far. J. Davy, in his second 

 experiments, recognized this fault in his first observations. As the results ob- 

 tained by Magnus are generally quoted and received in works on physiology, we 

 give the table, which is taken from the translation of his original article in the 

 Annales de C/iimie et de Physique (loc. cit.'). We have not thought it worth while 

 to reduce the volumes from cubic centimetres to cubic inches, as we add the 

 percentage of gas in volume, which is not given by Magnus. 



{5-4 of carbonic acid, or 4-32 per cent. 

 1-9 of oxygen, or 1'52 per cent. 

 2-5 of nitrogen, or 2'00 " 



Venous blood of the same, ) t 8-8 of carbonic acid, or 4-29 per cent, 



four days after the tak- V205 c.c. gave 12'2 c.c. of gas-j 2-3 of oxygen, or 1-12 per cent. 



ing of arterial blood \ ( 11 of nitrogen, or 0-54 " 



I lO'O of carbonic acid, or 5'12 per ct. 



The same blood 195 c.c. gave 14-2 c.c. of gas- 2-5 of oxygen, or 1-28 per cent 



/ 1-7 of nitrogen, or 0-82 " 



Arterial blood of a horse 1 I 10'7 of carbonic acid, or 8'23 per ct. 



very old, but in good V 130 c.c. gave 16'3 c.c. of gas-< 4'1 of oxygen, or 3'15 per cent 



health ) ( 1'5 of nitrogen, or 1 -15 " 



( 7*0 of carbonic acid, or 5'74 per cent 



The same blood 122 c.c. gave 10"2 c.c. of gas-( 2-2 of oxygen, or 1-80 per cent 



( 1 -0 of nitrogen, or 0'82 " 



Venous blood of the same ) ( 12'4 of carbonic acid, or 7'29 per ct. 



old horse, drawn three V170 c.c. gave 18'9 c.c. of gas-< 2-5 of oxygen, or 1'47 per cent. 



days after ) ( 4-0 of nitrogen, or 2'35 ' 



i 9'4 of carbonic acid, or 7*64 per cent 



Arterial blood of calf 123 c.c. gave 14'5 c c. of gas-; 3-5 of oxygen, or 2-84 per cent. 



/ 1-6 of nitrogen, or 1-30 " 



( 7*0 of carbonic acid, or 6'49 per cent. 



The same blood 108 c.c. gave 12'6 c.c. of gas-< 3-0 of oxygen, or 2-87 per cent 



( 2-6 of nitrogen, or 2-40 " 



Venous blood of the same ) ( 10-2 of carbonic acid, or 6'66 per ct 



calf, taken four days >153~c.c. gave 13 3 c.c. of gas-c 1*8 of oxygen, or 1-17 per cent. 



after i ( 1-3 of nitrogen, or 0'85 " 



( 6'1 of carbonic acid, or 4'35 per cent 



The same blood 140 c.c. gave 7'7 c.c. of gass I'O of oxygen, or 0*71 per cent 



( 0'6 of nitrogen, or 0'43 " 



We have given this table in full, and calculated the percentage of gas to the 

 blood in each observation, because it is a common impression that the observa- 

 tions of Magnus show a greater proportion of oxygen in the arterial blood, and a 

 greater proportion of carbonic acid in the venous blood. This is not the fact. 

 The table shows that the proportion of all gases is greater in the arterial blood, 

 and that the proportion of carbonic acid to the oxygen is greater in the venous 

 blood ; but while the percentage of oxygen is greater in the arterial blood, there 

 is also a larger percentage of carbonic acid. In the specimens of arterial blood 

 examined, the mean proportion of oxygen was 2'44 per cent., and of carbonic 

 acid 6 '48 per cent. In the venous blood, the mean proportion of oxygen was 

 1'15 per cent., and of carbonic acid, 5 '54 per cent. It is difficult to reconcile an 

 analysis, showing a greater absolute quantity of carbonic acid in arterial than in 

 venous blood, with our settled and well-sustained ideas regarding the processes 

 of respiration. A glance at the wide differences in the different analyses of speci- 

 mens of the same blood shows that there must have been some grave error 

 in the process. 



