RESPIRATION 



169 



The crystals of haemoglobin from different animals are 

 different in shape ; in most cases they are rhombic (horse, 

 dog, man, etc.), but in other cases they are hexagonal plates 

 (squirrel) or [tetrahedra (guinea-pig). 



FIG. 39. Blood Spectra. 



1. Oxyhaemoglobin. 



2. Haemoglobin (reduced). 



3. Carboxyhaenioglobin. 



4. Acid haematin. 7. Methaemoglobiu. 



5. Alkaline haematiii. 8. Haanatoporphyrin. _ 



6. Reduced Hajmatin. 9. Wave lengths in 10 



of a ram. 

 (From " Human Physiology, "A. D. Waller. Longmans.) 



TRANSPORT OF CARBON DIOXIDE 



The transport of carbon dioxide is a much simpler problem 

 than the transport of oxygen, parbon dioxide is more soluble 

 than oxygen in water, hence more of it can be carried in 

 solution. It combines with alkalies to form carbonates and 

 bicarbonates, hence we find that some of the carbon dioxide 



