OF HEMOGLOBIN, AND ITS SPECIFICITIES. 



79 



1.61 and 1.63. Miiller (Archiv f. ges. Physiologie, 1904, cm, 541) in studies 

 of freshly drawn blood, after three years' experience with the spectrophotom- 

 eter, has cast doubt upon certain of Hiifner's teachings regarding extinction 

 coefficients, etc. He found that the relations of the extinction coefficients 

 of the blood taken directly from the animal are not as constant as Hiifner 

 states, and in opposition to Hiifner he holds that values which differ from 

 1.56 are not necessarily wrong. He goes on to state that Hiifner looks upon 

 all values which differ materially from 1.56 as wrong, which Hiifner explains 

 by the formation of methemoglobin. This explanation seems to Miiller to be 

 untenable, since he found in examinations of freshly drawn blood from the 

 ears of a dog a value of 1.47 to 1.49, which figure Hiifner would designate as 

 incorrect, and yet it was fresh blood taken from the healthy animal, so that 

 we must either accept the presence of methemoglobin in the apparently 

 normal animal, or else material individual differences in the optical con- 

 stants of oxy hemoglobin. The second probability seems to Miiller more 

 likely, and he goes on to state that it should not be left unmentioned that 

 Torup observed by means of the Glan photometer, after the addition of a 

 little sodium bicarbonate to the diluted hemoglobin solutions, a shifting 

 of the point of strongest absorption; and also, as Bohr states, an insignificant 

 change of the hemoglobin, which has no influence whatever either upon the 

 molecular weight or the amount of absorbed oxygen, may give an entirely 

 different value in light absorption. Changing alkalinity of the blood seems 

 therefore to have a disturbing influence, as has been found by others. 



TABLE 28. Extinction coefficients in different orders of animals. 



In a more recent inquiry with fresh blood, Aron, Hans, and Miiller 

 (Archiv f. Anat. u. Physiologie, 1906, Suppl. Bd., 109) throw even more 

 serious doubts upon Hiifner's assertions as to the constancy of the extinc- 

 tion coefficients. The average quotient they found to be about the same 

 in different species (dog, horse, cat, ox, and rabbit), but 55 out of 142 cal- 

 culations differ much more from the average value than can be explained 

 by the greatest possible errors that can be accounted for in errors of method 

 or by variations in the strength of solution. Moreover, the average value 

 was found to be 1.47, whereas Hiifner's is 1.578. Light absorption they 

 found to be in direct relation to the quantity of iron, and approximately 

 the same for the blood of the rabbit, ox, and dog, but varying somewhat 

 for the blood of the horse. They suggest that methemoglobin normally 

 exists in the blood, which may account for differences in Hiifner's and 

 Bohr's results in their studies of oxyhemoglobins. They also point out 

 that by the regular method of defibrinating the blood there occurs a loss of 

 hemoglobin which does not occur if the defibrinization be effected by agi- 

 tation in a closed vessel. 



