64 HEMOGLOBIN 



you concentrate the corpuscles into a creamy mass in a centrifuge, 

 draw ofiE the plasma, wash the corpuscles two or three times with 

 saline, then add sufficient alcohol (or ether) to lake the blood and 

 throw down the crystals. Having obtained the crystals you wash 

 them with ice-cold water on a porous plate, you then dry them, put 

 them in a bottle which you label "haemoglobin," and there they are. 

 You may have an easy mind so long as you refrain from asking your- 

 self the following question: "What relation does the brown powder 

 in the bottle bear to the pigment which existed in the corpuscles? " 



In many ways we have more to learn about the condition of 

 haemoglobin in the interior of the corpuscles than was supposed 

 twenty or thirty years ago ; nevertheless this much may be said upon 

 the chemical side, haemoglobin behaves in some ways like an acid, in 

 others like an alkali. For instance it unites with such dyes as stain 

 oxyphil granules indicating that it has certain basic properties. The 

 colour which it assumes when stained with eosin for example depends 

 rather upon the number than upon the strength of such affinities, 

 and there is no reason for connecting them particularly with the 

 haematin rather than the protein part of the molecule. In the main, 

 however, haemoglobin must be regarded as an acid, and oxyhaemo- 

 globin as a stronger acid than reduced haemoglobin. In the corpuscle, 

 the reaction of which is on the alkaline side of neutral, it may be 

 supposed that we have a salt of the acid, this salt being the sodium, 

 or potassium salt, according to the animal concerned ; whilst in some 

 animals there will be a mixture of the two. In oxygenated blood 

 corpuscles, therefore, the interiors of which are buffered, probably the 

 haemoglobin will be present to some extent as the acid, but principally 

 as the sodium or potassium salt and perhaps as a mixtmre of the two. 



To what extent does the above method tend to preserve these 

 relationships? It is obvious that the mere laking of the corpuscles 

 and setting free of the pigment mixes the bases of the interior of the 

 corpuscle with those of the exterior, and therefore the base present 

 in the crystals may be largely that of the fluid in which the corpuscles 

 were suspended. The cure would seem to be that in washing the 

 corpuscles the fluid used should not be the ordinary physiological 

 saline, but a saline made up on a basis of sodium chloride, bi- 

 carbonate, etc., if the corpuscles are such as contain sodium, whilst 

 if the corpuscles contain potassium the saline should contain potassium 

 salt. A greater source of solicitude is the advisability of using 

 alcohol or ether at aU. 



