182 



HEMOGLOBIN 



could be clamped and the whole apparatus warmed up rapidly by 

 replacing the water in the bath by water at a higher temperature. 

 The flow of nitrogen was then resumed at the altered temperature. 



Nitrogen was allowed to run for 36 minutes by which time the 

 haemoglobin was slightly reduced. An analysis showed that 6 per 

 cent, of the haemoglobin was reduced haemoglobin and 94 per cent, 

 was oxyhaemoglobin. The point at which we arrived is represented as 

 D on Fig. 61. There is possibly an error of about 2 per cent, in this 

 measurement either way, i.e. the percentage saturation may have 

 been 92 per cent, or 9^ per cent, {d or d'). The nitrogen was stopped, 

 the temperature of the bath was raised to 38° C. (the time taken 



Fig. 61. Curve representing the calculated degree of dissociation, at any time, of 

 haemoglobin, which was reduced by a stream of nitrogen bubbled at a uniform 

 rate. Percentage saturation plotted vertically, time in minutes horizontally. 

 The points represent actual determinations: A~D at 18° C, D-G at 38° C. 



for the change is omitted from the diagram), and the nitrogen was 

 re-started. The haemoglobin now became reduced very rapidly. After 

 this three other determinations were made as follows: 



Point on curve ... ... 



Time (minutes) measured from Z) 

 Percentage saturation of haemoglobin . . . 



Thus, whilst at 18° C, 35 minutes had been required for the reduction 

 of haemoglobin from 100 to 94 per cent, saturation, at 38° C. it only 

 required 7-5 minutes to reduce it from 94 to 77 per cent. Perhaps the 

 best comparison of the times necessary to produce a given reduction 

 is that obtained by extrapolating the curve DEFG backwards to B, 

 in which case AC represents the time necessary to produce the 



