CHAPTER XVI. 



CRYSTALLOGRAPHY OF THE HEMOGLOBINS OF THE FELIDJE 

 AND VIVERRID^E CATS AND CIVETS. 



Nine species of the cats and one species of civet were studied, includ- 

 ing, of the genus Felis, the lion, Bengal tiger, jaguar, puma or mountain-lion, 

 leopard-cat, ocelot, and common domestic cat; and of the genus Lynx the 

 wild cat or bob-cat and the lynx. The civet examined was the binturong, 

 Arctictis binturong. 



As in the case of the dogs, the hemoglobin crystals of the cat tribe 

 form a strictly isomorphous group; but in the case of the Felidce it is 

 common to obtain the crystals of reduced hemoglobin, which is not 

 the case of the dogs. The fresh blood of the cats, especially of the Old 

 World species that were examined, gave crystals of reduced hemoglobin, 

 along with those of oxyhemoglobin, in the first crop of crystals to form; 

 or frequently the reduced hemoglobin crystallized alone, with no oxy- 

 hemoglobin. The oxidation of the blood by exposure to air or to pure 

 oxygen would generally produce crystals of oxyhemoglobin in such cases. 

 The blood of the common cat, freshly obtained, crystallizes first as reduced 

 hemoglobin, and crystals of oxyhemoglobin are apparently not produced. 

 But the solution contains much oxyhemoglobin, and the probability is 

 that the oxyhemoglobin crystals are much more soluble than those of the 

 reduced hemoglobin, as appears to be the case in all species of cats. The 

 lion, tiger, leopard-cat, and ocelot also gave the crystals of reduced hemo- 

 globin very readily, but, in the blood of the lion and leopard-cat, crystals of 

 oxyhemoglobin were also observed. In general, the Old World cats seemed 

 to develop reduced hemoglobin very readily in their blood, and there seemed 

 to be a large amount of it present. The New World cats, the jaguar and 

 puma, as well as the bob-cat and the lynx, all gave crystals of oxyhemo- 

 globin readily, and while these were more soluble than the crystals of the 

 reduced hemoglobin of the same species, they formed readily in fresh or 

 oxygenated blood and grew to large size. In the case of the mountain- 

 lion, two forms of oxyhemoglobin were observed, and the same was true 

 of the jaguar; while two forms of reduced hemoglobin were observed in the 

 case of the lynx. 



The oxyhemoglobin in the cats is thus dimorphous or trimorphous, 

 and the reduced hemoglobin also appears to be dimorphous. The reduced 

 hemoglobin crystals, being formed more constantly than the oxyhemoglobin 

 crystals, give a better basis for comparison of the species; but, even with 

 these reduced-hemoglobin crystals forming in large quantity, they were 

 often so imperfectly formed that the axial ratios could not be made out. 



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