194 



CRYSTALLOGRAPHY OF HEMOGLOBINS OF THE UNGULATES. 



velopment of the dome faces; the prisms are often flattened on two opposite faces, but 

 usually symmetrically developed. They frequently grow in radiating groups and in 

 some cases appear to be twinned on a pyramid of the unit series (text figure 116) but 

 the angle of this pyramid was not determined. Parallel growths of two crystals, side 

 by side with a common dome edge, are frequently seen. Some of the prismatic crystals 

 are very long, the ratio of length to thickness being 20 : 1 or more. 



115 



114 



FIGS. 114, 115, 116. Equua coballui a-Carbon-monoxide Hemoglobin. 



Pleochroism is not so strong as in the oxyhemoglobin, but a is pale rose-pink and 

 b and c nearly equal and rose-red. The spectrum was that of CO-hemoglobin as deter- 

 mined by the microspectroscope. The orientation of the elasticity axes is a =6, b=b, 

 c=a; the plane of the optic axes is the brachypinacoid; the optical character, judging 

 from the pleochroism, is negative, and the acute bisectrix, Bx a =a. 



{3-CO-hemoglobin of Equus caballus. 



Monoclinic: Axial ratio a : b : 6 = 1.664 : 1 : 6; /? = 68. 



Forms: Unit prism (110), positive hemiorthodome (T01), base (001). 



Angles: Prism angle, traces of the prism on the base, edges 110-001 A lTO-001 = 

 62; angle of the hemiorthodome on the base not obtained; prism edge to base, edge 

 1 10-110 A 001=68. 



119 



a 



FIOB. 117. 118, 119. Equus caballus 3-Carbon-monoxide Hemoglobin. 



Habit thin tabular on the base, consisting of the base cut by the unit prism (110) 

 (text figures 117 and 118) and in some cases by the hemiorthodome (101) also (text 

 figure 119), often this form appearing on one end of the plate only. This hemiorthodome 

 was also observed in some of the twins. Twinning is normal in these crystals; an un- 

 twinned crystal is exceptional. The usual twin (horse-type) is on the normal to a common 

 prism-base edge as twin axis, the normal lying in the base and the plane of twinning, 

 hence a plane including the prism-base edge and normal to the base as already described 

 under /3-oxyhemoglobin of the horse. The majority of these crystals consist of at least 



