THE RED BLOOD CORPUSCLES 865 



results according to the animal employed. In the case of the oxyhaerno- 

 globin of the dog, Jaquet obtained the following figures : 



In 100 parts 



C . . 53-91 .. 54-97 



H 6-62 .. 7-22 



N 15-98 .. 16-38 



Fe 0-333 . . 0-336 



S 0-54 .. 0-568 



O 22-62 .. 20-93 



The chief differences between different animals appear to have relation 

 to the sulphur. Haemoglobin from the hen contains 0*857 per cent, sulphur. 



II specimens are alike in containing a constant proportion of iron, as is 

 own in the following Table : 

 Oxyhsemoglobin of Fe per cent. Authority 



Dog 0-336 .. Jaquet. 

 Horse 0-335 .. Zinoffsky. 

 Ox .... 0-336 . . Hiifner. 

 Hen . 0-336 . . Jaquet. 



On the assumption that each molecule of oxyhaemoglobin contains one 

 atom of iron, its molecular weight would be 16,660, and this result is borne 

 out by the volume of oxygen or carbonic oxide which can enter into combina- 

 tion with haemoglobin. It has been suggested by Bunge that the enormous 

 size of the haemoglobin molecule finds a teleological explanation; if we 

 consider that iron is eight times as heavy as water, a compound, which would 

 float easily along with the blood current through the vessels, could be secured 

 only by the iron being taken up by so large an organic molecule. Oxy- 

 haemoglobin is a compound in definite proportions of oxygen and haemo- 

 globin or reduced haemoglobin. It can be easily dissociated and is split up by 

 such simple means as exposure to a vacuum. If, for instance, some arterial 

 blood or solution of oxyhaemoglobin be introduced into a Torricellian 

 vacuum, the fluid is seen to give off bubbles of gas, and the colour changes 

 from a brilliant scarlet to a dull bluish red. In this process each gramme of 

 oxyhaemoglobin gives off 1-34 c.c. of oxygen. The same change can be 

 effected by treating a solution of oxyhaemoglobin with reducing agents such 

 as an alkaline solution of ferrous tartrate (Stokes's fluid) or ammonium 

 sulphide ; in the latter case reduction is aided by gently warming the solu- 

 tion. Another reagent of value for effecting the reduction of oxyhaemoglobin 

 is a solution of hydrazine. The oxygen in oxyhaemoglobin can be replaced 

 by equivalent quantities of other gases. Thus if carbon monoxide gas 

 be led through a solution of oxyhaemoglobin, oxygen is given off and its' 

 place is taken by an equal volume of carbon monoxide with the formation of 

 a more stable compound, carbon monoxide haemoglobin. This body is dis- 

 iated only with extreme slowness and is unaffected by the addition of 

 ucing agents. By using special precautions to prevent oxidation of the 

 , the carbon monoxide can be replaced in this compound by nitric oxide, 

 55 



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