W. N. M. RAMSAY 



ferrihaemoglobin might be measured by this method. This work 

 was repeated and greatly extended by F. J. W. Roughton, R. C. 

 Darling and W. S. Root 11 . The amounts of ' inactive haemoglobin ' 

 which they found were not generally as large as those noted by 

 Ammundsen, but a most interesting additional observation was made : 

 that if the bloods were allowed to stand in the laboratory, the inactive 

 haemoglobin disappeared ; that is to say, the carbon monoxide 

 capacity gradually increased until it attained the value initially 

 observed only after reduction with hydrosulphite. The oxygen 

 capacity was also observed to increase in blood specimens which 

 were allowed to stand in air, but these authors did not make any 

 estimates of the oxygen capacities after reduction. 



An unfortunate defect of the carbon monoxide method, at any 

 rate in theory, is its lack of specificity. Carbon monoxide will combine 

 not only with ferrohaemoglobin, but also with sulphhaemoglobin, 

 choleglobin and several ferrohaemochromogens. A more specific 

 technique, however, has been a possibility since J. B. Conant, N. D. 

 Scott and W. F. Douglass 12 discovered that ferrihaemoglobin could 

 be estimated from the increase in oxygen capacity resulting from 

 reduction with an alkaline titanous tartrate solution. The original 

 method required relatively large volumes of blood and was tedious 

 to operate, but the present author was fortunate in being able to 

 simplify the technique without sacrificing accuracy 13 . The modified 

 method was applied to the analysis of 38 normal human blood 

 specimens, and significant differences were found between the apparent 

 oxygen capacities before and after reduction in 21 of these. The 

 author then believed it likely that the differences were due to the 

 presence of ferrihaemoglobin. The largest difference noted amounted 

 to 7 per cent of the total pigment present, but most of the values lay 

 between 1-5 per cent and 3 per cent. A number of differences of 

 the order of 1 per cent were observed, but these were not considered 

 at that time to be large enough to be statistically significant. Allowing 

 the specimens to stand in the laboratory caused an increase in 

 apparent oxygen capacity up to the value initially obtained after 

 reduction (cf. Roughton et ah 11 ), and in a later paper on horse and 

 sheep bloods 14 a close correspondence was noted between the oxygen 

 capacity after reduction with titanium and the total iron concentration. 

 This last observation demonstrates the absence from normal bloods 

 of haemochromogens and other haemoglobinoid pigments which do 

 not combine with oxygen even after reduction, and hence justifies the 

 use of the carbon monoxide technique employed by the other workers. 



The accuracy of all gasometric methods depends on several factors, 

 among which we may mention the technique for the determination 



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