Composition of Blood Gases during Respiration of Oxygen. 57 



different animals cannot be identical in all respects. C. G. Douglas,* using 

 rabbits as the subject of his experiments and the Gowers-Haldane hsemo- 

 globinometer to determine the percentage oxygen capacity of blood, considers 

 that a parallel relationship exists between the oxygen capacity of the blood 

 and the depth of its colour as judged by the haemoglobino meter, and it was 

 essential for our purpose to ascertain if this was true for cats. 



In the case of cats we have found that there is complete agreement 

 between the actual values for oxygen as determined with our pump and that 

 of the oxygen capacity by the Inemoglobinometer. We used hirudinised 

 blood of cats ; the saturation method, determined in vitro at 38° C, has been 

 described in a former paper.f 



Percentage Oxygen Capacity of Blood. 





By pump. 



V>\ i].-i'inoi;iol»i'i<mu'l..'r 



A 



16 -52 



17 "39 hirudin. 



B 



21 -04 



19 -89 defibrinated blood. 



i 



19 -48 



19-89 hirudin. 



D 



17 -24 



16 -56 



Mean 



18 -57 



18 -43 



Difference + *14 c.c. per 100 c.c. blood. 



This supports the contention of those who believe that no valid argument 

 exists against the view that the htemochromogen moiety of the molecule of 

 haemoglobin is identical in all animals. 



Composition of the Blood Gas for Animals Breathing Air and Oxygen 

 respectively. 



In Table I we give for eats under urethane anaesthesia : — 



1. The composition of the blood gases. 



2. Percentage haemoglobin value. 



3. Calculated theoretical oxygen capacity per 100 grm. of blood. 



4. Calculated percentage saturation of haemoglobin. 



5. Calculated percentage saturation of haemoglobin from the percentage 

 composition of alveolar air, making use of the blood dissociation curve given 

 by J. Barcroft and M. Camis for dog's blood.J 



G. The percentage composition of alveolar air. 

 * ' Journ. Physiol.,' 1910, vol. 39, p. 453. 



t ' Journ. Physiol.,' 1912, vol. 43, No. 6, p. 410. In Experiment XIV, Table III, the 

 second oxygen figure in the blood-gas analysis should read 17"24 instead ofl3 - 59. 

 % ' Journ. Physiol.,' 1909, vol. 39, p. 132. 



