288 



CRYSTALLOGRAPHY OF THE HEMOGLOBINS 



simultaneously. All of these forms appear to be the same substance, and 

 to have the same axial ratio. They were all oxyhemoglobin as determined 

 by the microspectroscope. They will be designated types (a), (b), and (c). 

 From the pyramidal type, by twinning in sixlings, are produced mimetic 

 crystals, that finally become isometric in angles and isotropic in structure. 

 These are distinguished from the first three kinds enumerated as /3-oxy- 

 hemoglobin, while they types (a), (b), and (c) are designated as a-oxy- 

 hemoglobin. 



The first crystals to appear, type (a), have a somewhat porous aspect; 

 they tend to be dissolved, and the same is true of the tabular crystals; but 

 the pyramidal-looking crystals of the a-oxyhemoglobin and their mimetic 

 twins, the /3-oxyhemoglobin, are more permanent. The thin plates desig- 

 nated as type (c) of the a-oxyhemoglobin are somewhat more soluble than 

 the type (a) prisms; and the latter recrystallize readily. 



Later, crystals of reduced hemoglobin developed in the slides; they 

 were well formed and showed no tendency to dissolve, but they only 

 appeared very sparingly and in a few slides. 



a-Oxyhemoglobin of Felis concolor. 



Orthorhombic : Axial ratio a : b : 6 =0.9489 : 1 : 1.5546. 



Forms observed: Unit prism (110), macroprism (210), brachydomes (Oil), (013); 

 macropinacoid (100), brachypinacoid (010), base (001). 



Angles: Prism angle 110 A 1TO=87 (normals); also measured as 85 on some 

 crystals; brachydomes Oil A Oil =65 30', 013 A 013=54 (about). 



FIGS. 328, 329, 330, 331, 332. Felit concolor a-Oxyhemoglobin. 



Habit at first prismatic on the vertical axis, the crystal consisting of the unit prism 

 and brachydome, type (a) (plate 85, figs. 507 and 508; also text figure 328). In these 

 crystals the ratio of length to thickness is about 4:1. These are succeeded by type (b) 

 crystals (see text figure 329 and plate 85, figs. 509 and 510), consisting of the macroprism 

 prism (210) with the brachydome (013) in about equal development, the combination 

 making a rather pyramidal-looking crystal resembling a regular tetragonal pyramid. 

 With these also appear very thin plates, type (c) (plate 86, fig. 511) ; four, six, and eight- 

 sided; consisting of the base bounded by the unit prism and the two vertical pinacoids 

 (001) (110) (100) (010) (text figures 330 and 331). These type (c) crystals are evidently 

 the same as the large plates found in the blood of the jaguar and lion and several other 

 cats; but in this case they are not the normal type of crystal. Of these three types of 

 crystal the type (b) appears to be the most permanent, the other two seem to show a 

 tendency to dissolve and recrystallize as type (b). 



