CRYSTALLOGRAPHY OF HEMOGLOBINS OF THE UNGULATES. 



215 



Habit prismatic, the first crystals to form consisting of the unit prism and brachy- 

 dome (054) in prisms about 4 times as long as the width on the macro-axis (see text 

 figure 174). Later, as the solution becomes more concentrated, other planes develop 

 and the brachyprism (120) predominates, the unit prism being reduced to a bevel on the 

 brachyprism; in these crystals the two brachydomes (Oil) and (054), the former predom- 

 inant, sometimes develop with a small macrodome (302) (text figure 175) or the pyramid 

 (221) with (054) and (302) (text figure 176). The crystals from the concentrated solution 

 are hence of two types, in both of which the prism taken as the brachyprism predomi- 

 nates; but both of these types occurred sparingly and in a few slides. The crystals often 

 grow in tufts from the oxalate crystals which separate from the supersaturated oxalate 

 solution; usually, however, they occur singly, scattered through the slides or massed in 

 the protein ring and along the cover edge. Twinning was observed on a pyramid, which 

 appears to be the observed pyramid (221) ; these are interpenetrant twins (text figure 177). 



The deep color of the solution in most cases conceals the pleochroism, but in thin 

 slides it is quite marked; a is colorless to pale red; & is pink to red; c is deep blood-red; 

 on sections showing b and c the pleochroism is not pronounced. Extinction is straight 

 in all aspects of the crystals. The orientation of the elasticity axes is a =6, b=a, c=6. 

 The plane of the optic axes is hence the macropinacoid; and on basal sections in con- 

 vergent light the biaxial interference figure is visible with the axes rather widely sepa- 

 rated, 2E=75, about. The axis of greatest elasticity a is hence the acute bisectrix, 

 Bx a = a and the optical character is negative. 



A 



A 



178 



FIGS. 174, 175, 170, 177. Bos laurua Oxyliemoglobin. FIG. 178. BOB biton Oxyhemoglobin. 



BUFFALO, Bos bison. Plate 44. 



The specimen was received from the Philadelphia Zoological Gardens 

 in a very putrid condition. It was centrifugalized, and preparations made 

 in the usual manner. The blood showed the spectrum of oxyhemoglobin, 

 but with some traces of methemoglobin; the crystals, which formed readily 

 at room temperature, showed only oxyhemoglobin. While the crystals 

 formed readily, they were not well developed, and the determination of 

 their characters was unsatisfactory. Their description is as follows: 



Oxyhemoglobin of Bos bison. 



Orthorhombic : Axial ratio only approximately determined ; a : b : 6 = a : 1 : 0.5095. 



Forms observed: Macropinacoid (101), brachypinacoid (Oil), brachydome (Oil). 



Angles: The angle of the brachydome was measured at about 126 actual angle. 

 This is the angle of the brachydome of the bullock oxyhemoglobin (054) crystals, which 

 is 126 actual angle. The measurements of the bison crystal may be 1 out of the way. 



