HEMOGLOBIN 277 



I. HEMOGLOBIN 



The exuding drop of blood shows even to the naked e,ye a number of prop- 

 erties. The redder it is, the richer it is in oxyhemoglobin; the darker, the 

 greater the amount of reduced hemoglobin. Accordingly, it is at once recog- 

 nized from these properties whether the blood originates from the arterial and 

 capillary vessels or from the venous system. In carbonic acid poisoning the 

 color of the blood is particularly bright and, as a rule, is designated as 

 cherry-red. 



In the red oxjfgen-containing blood differences in the intensity of the color- 

 ing are readily determined, but these are frequently not easy of recognition 

 in very dark venous blood. Such differences become more noticealile if the 

 drop of blood is caught and spread out upon white linen or upon white blot- 

 ting paper ; the greater or lesser staining power of different drops of blood is 

 very well demonstrated in this simple manner, and, with some practice, from 

 the color of the stain a conclusion may be drawn as to the amount op hemo- 

 globin in the blood. Following this principle, Tallqvist has described a 

 " hemoglobin scale " by the aid of which gross differences in the amount of 

 hemoglobin may be quite accurately estimated. [The Tallqvist scale gives us 

 not ideal accuracy but all the accuracy that we can use in diagnosis, prognosis 

 and treatment. Its errors rarely exceed 10 per cent., and in the hands of the 

 unskilled other and more " accurate " instruments often show more errors than 

 this. The cheapness of the scale and the ease and quickness of using it are 

 also important recommendations. — Ed.] 



Accuracy is greater with apparatus especially constructed for the estima- 

 tion of the coloring power of the blood, the so-called hemoglobinometer. This 

 apparatus is quite properly named ; for, in the main, it is the amount of hemo- 

 globin contained which determines the coloring property of the blood; the 

 importance of a few other coloring substances contained in the blood is in 

 comparison quite insignificant. 



For clinical purposes a large number of blood colorimeters have been de- 

 scribed; on account of their simplicity Gowers's hemoglobinometer and 

 Pleischl's hemometer are most used, and will now be described (Dare and 

 Oliver). 



The principle of the Fleischl hemometer, as modified by Miescher, is the 

 following: By the aid of a pipette which is furnished with the apparatus (Fig. 9 

 Mel.) an exactly determined amount of blood is dissolved in a measured quan- 

 tity of distilled water; the color of this solution is compared with that of a 

 colored glass wedge which, by its gradually increasing thickness, represents a 

 scale of blood concentrations. The point in the wedge is now searched for 

 which is Just as intensely colored as the solution of blood that is to be exam 

 ined, and the number is read off Avhich is found at this point of the glas: 

 wedge. If, for example, the color of the blood solution is equal to that desig- 

 nated as 75 in the glass wedge, it means that the examined blood contains 

 75 per cent, of the normal amount of hemoglobin. Besides the estimation 

 of the percentage of hemoglobin, this apparatus also makes it possible to 



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