194 



PRACTICAL PHYSIOLOGY 



removing the serum with a pipette, shaking up the corpuscles with a 

 0*9 per cent, sodium chloride solution 1 (which is nearly isotonic for the 

 blood of the ox, horse, or man), and again centrifugalising, 



By this means the corpuscles are thoroughly washed free of serum, 

 etc. They are then collected and treated with two or three times their 

 bulk of distilled water, in which the haemoglobin dissolves, a deep red 

 solution resulting. 



FIG. 142. Haemoglobin crystals. X 800. 



The solution gives several of the ordinary proteid reactions, but in 

 each case a splitting into proteid and haematin simultaneously ensues. 



EXPERIMENT IV. Heat carefully some haemoglobin solution. It 

 decomposes at about 60 C., and the proteid coagulates on further 

 heating. 



1 A salt solution of this strength has the same osmotic pressure as the contents 

 of the red blood corpuscle, and consequently no swelling or crenation of the 

 corpuscle is produced. 



