42 Chapter IV 



shown that, even taking this fact into consideration, the blood of the 

 dog had a smaller affinity for oxygen than had that of the horse. 



Camis (5) and I determined to perform some experiments to test 

 the accuracy of the above observations : this did not seem difficult 

 in view of the fact that we had at hand the differential method 

 of blood gas analysis a method which offered the prospect of 

 making in a few days analyses that would previously have taken 

 many weeks. 



Like those of the proverbial golfer who strikes the ball with un- 

 erring accuracy on the occasion of his first visit to the links and then 

 only, so our very early efforts seemed to augur speedy success in 

 our case the construction of a uniform dissociation curve for the blood 

 of various animals. When we came to the blood of man however we 

 could never make the dissociation curve agree with that of the cat or 

 the rabbit. We went back to it time after time ; the result was the 

 same, human blood took up less oxygen at low tension than did that 

 of the cat or rabbit. It was then clear that we had found our way 

 into the morass in which our predecessors had already floundered so 

 hopelessly, and our newer and more certain methods instead of saving 

 us from their embarrassments had only made the uncertainty of our 

 position more certain. There was no overlapping of the curves, no 

 confusion of the points human blood had a smaller affinity for 

 oxygen than cat's blood. 



We then entered upon six months of research which became 

 weekly more and more depressing. Occasional flickers of light ap- 

 peared they turned out to be but will-o'-the-wisps each of which 

 beckoned us to a more inevitable disappointment than the last. It is 

 easy to discuss the merits of apparatus, to gauge the help given by 

 this or that method, yet as I look back upon this period of gloom, I 

 discern more and more clearly as time goes on that the determining 

 factors which made this research fruitful did not come from methods 

 or from apparatus, but from the unfailing zeal and good will of my 

 colleague Camis. His goodness of heart rose superior to the trials 

 caused not only by his own disappointments but by mine. 



We thought to simplify the issue by ceasing to work with blood 

 and substituting haemoglobin. The simplest way of making this 

 substitution was to lake the blood. In order to do this efficiently we 

 added an equal part of dilute ammonia solution such as we used in 

 our gas analysis apparatus, which solution was made by adding 4 c.c. 

 of strong ammonia to a litre of distilled water. 



