198 



HEMOGLOBIN. 



blood-colouring matter, it is advisable to consider its elementary com- 

 position, and to ascertain how the results of chemical analysis bear on 

 the question as to haemoglobin being a definite chemical individual, its 

 composition being invariable. 



Haemoglobin is a compound of carbon, hydrogen, nitrogen, sulphur, 

 iron, and oxygen. The crystals of haemoglobin contain water of crystal- 

 lisation, which varies considerably in amount in the haemoglobin of 

 different animals. When ignited, pure haemoglobin obtained from 

 mammalian blood yields an ash composed entirely of ferric oxide ; the 

 haemoglobin of birds and fishes, and probably of all animals with 

 nucleated corpuscles, yields on ignition an ash which, in addition to 

 Fe 2 3 , contains phosphoric anhydride (l^Oj), derived in all probability 

 from nuclein contained in the corpuscles. 1 



The earlier analyses of oxyhaemoglobin made by C. Schmidt 2 and 

 by Hoppe-Seyler 3 exhibited results which appeared to indicate that 

 crystallised oxyhsemoglobin is a body of constant composition. From 

 the analyses of these two observers, and his own determinations of the 

 iron and sulphur in crystallised oxyhaemoglobin, Preyer deduced the 

 following as the mean percentage composition of oxyhaemoglobin : 



In 100 Parts. 



C 

 H 

 N 



Fe 



S 



o 



54-00 

 7-25 



16-25 

 0-42 

 0-63 



21-45 



100-00 



On the assumption, which a large number of facts have since shown 

 to be almost certainly correct, that the molecule of haemoglobin contains 



one atom of iron, Preyer assigned to it the empirical formula C c 

 N 154 FeS 3 170 , the molecular weight being 13,332. 



Jl < 



Analysis of Oxyliwrnoglobin dried at a temperature above 100 C. 5 (Hoppe-Seyler). 



1 Y. Inoko, " Einige Bemerkungen ueber phosphorhaltige Blutfarbstoffe," Ztschr. /. 

 physiol. Chem., Strassburg, 1894, Bd. xviii. S. 57. 



2 " Analyse der Blutkrystalle," in Bottcher's monograph, "Ueber Blutkrystalle," 

 Dorpat, 1862. 



3 "Beitrage zur Kenntniss des Blutes des Menschen mid der Wirbelthiere ; Zusammen- 

 setzung der Farbstoffkrystalle des Meerschweinchen- und des Hunde-blutcs," Mcd. Chem, 

 Untersuch., Berlin, 1868, S. 186 et seq. 



