The Blood. 31 



proteid, yet crystallizes ; whilst its behaviour in the 

 dialyser is not that of a colloid but a crystalloid. It is one 

 of the most complex substances in organic chemistry, and 

 its molecule is a very large one. According to the analysis 

 of Kosel,* hemoglobin in the horse consists of: 



C 54-87 O 19-73 



H 097 S -65 



N 1731 Fe -47 



The empirical formula for this body, on the assumption 

 that the molecule contains one atom of iron, is given by 

 Zinoffsky as follows : 



C 7] ,H m(1 X, I4 FeSA 4 ,. 



Analyses have proved that oxy-ha?moglobin presents a 

 perfectly constant composition, and is remarkable in being 

 the only proximate constituent of the body containing 

 iron. 



The total amount of haemoglobin in a horse's body is 

 about 8*8 lbs. ; and the amount of iron contained in this is 

 about 257 grains. This calculation is based on the assump- 

 tion that the amount of blood in the body is 66 lbs. 



In the red blood cells hemoglobin exists in the propor- 

 tion of 86 per cent, to 94- per cent., whilst in the total 

 blood of the horse it forms 1315 per cent., in the ox 9 - 96 

 per cent., sheep 1034 per cent., and pig 127 per cent. 

 (Ellenberger). 



The younger the animal the less hemoglobin ; males 

 have more than females, and castrated animals more than 

 entires (G. Miiller).t 



Hemoglobin has a remarkable affinity for oxygen. The 

 laws relating to the absorption of gases by fluids and solids 

 do not apply to hemoglobin. It has been calculated that 

 15^ grains of this substance will absorb 0*95 cubic inches 

 of oxygen gas. We have mentioned that when hemoglobin 

 is charged with oxygen it is spoken of as oxy-hemoglobin ; 

 when it has discharged its oxygen, which it is capable of 



* Ellenberger's 'Physiologie der Haussiiugethiere.' f Ibid. 



