202 HAEMOGLOBIN. 



the discrepancies between the results of the ultimate organic analyses 

 yet made, the oxyhaemoglobin possesses the same molecular weight. 

 The concordance between the more recent determinations of the iron 

 of oxyhaemoglobin is well shown in the table given on the previous 

 page. 



On the assumption that one molecule of haemoglobin contains one 

 atom of iron, the molecular weight of the haemoglobin of the dog, horse, 

 ox, and hen would be 16,669, and this result is borne out, as will be 

 afterwards shown, by the volume of oxygen or of carbonic oxide which 

 enters into combination with the blood-colouring matter. 



In addition to the estimation of the iron in haemoglobin, that of 

 the sulphur has been carried out with remarkable care by Hlifner, 1 

 Zinoffsky, and Jaquet; and their results, whilst establishing that the 

 centesimal composition of the blood-colouring matter of all animals is 

 not identical, show that in haemoglobin the sulphur stands to the iron 

 in definite relations. 



Thus Zinoffsky's analyses appear to establish that in the haemoglobin 

 of the horse the sulphur is to the iron in the relation of two atoms of 

 the former to one of the latter element, and Hiifner has shown that 

 exactly the same relation obtains in the case of the haemoglobin of the 

 ox and the pig. On the other hand, Jaquet 's analyses of the haemo- 

 globin of the dog indicate that in it three atoms of sulphur correspond 

 to one atom of iron. When, in a subsequent section, we shall examine 

 the products of decomposition of haemoglobin, we shall show that, under 

 the influence of acids and alkalies, the blood-colouring matter breaks 

 up into an iron-containing body (of which the composition and the 

 properties vary, according to the presence or absence of oxygen during 

 the decomposition) and into an albuminous body or bodies. The 

 sulphur of haemoglobin belongs to the albuminous part of the molecule, 

 and the difference in the relation of S to Fe, brought out by the 

 researches of Hiifner, Zinoffsky, and Jaquet indicates that the albuminous 

 moiety of the haemoglobin molecule varies in different animals, and that 

 among the points of difference is the difference in the proportion of 

 sulphur. This point will be certainly cleared up by future researches 

 specially directed to its elucidation; it may be remarked, however, 

 that the proportion of sulphur in different albuminous bodies does 

 exhibit great variations. 



It appears to me, moreover, that we must not lose sight of the possi- 

 bility (even when there is no evidence afforded by ultimate organic 

 analysis -of there being a difference in the percentage composition of the 

 albuminous part of the haemoglobin moiety), and indeed probability, that 

 haemoglobins varying in certain physical properties may he formed by the 

 linking of the iron- containing molecule to various polymeric combinations of 

 the same albuminous molecule. 



Although it is highly probable that the molecular weight of the 

 haemoglobin of the dog and of the ox (16,669), as determined by the 

 iron determinations of Jaquet and Hiifner, and by determinations by 

 Hiifner of the volumes of O and CO with which haemoglobin combines, 

 has been ascertained with correctness, or nearly so, the discrepancies in 

 the results of the determinations of 0, H, and N, made by different 

 observers, are too great to warrant our placing confidence in the 

 empirical formulae which have been assigned to haemoglobin. Of these 



1 " Bestimmung d. Sauerstoffscapacitat d. Blutfarbstoffs, " S. 76. 



