OF PISCES, BATRACHIA, AND REPTILIA. 159 



a-Oxy hemoglobin of Python, molurus. 



Monoclinic: Axial ratio a : 6 : <! =0.900 :!:<*; /3=65 (about). 



Forms observed: Prism (110), base (001), orthopinacoid (100). 



Angles: Traces of 110 A 1TO on base =84 (normals); 100 A 001=65=^. The 

 angle of the prism varied from 81 to 86, but the best measurements ran very close 

 to 84. 



Habit (a), long lath-shaped crystals with oblique ends, due to elongation on the 

 ortho-axis, with the combination (001) (100), and two faces of the prism 110 and HO 

 (text figure 25) ; these appeared first in the fresh blood. Habit (b) tabular by development 

 on (001) with a short prism (110) (text figures 26, 27; also plate 7, figures 39 to 42); 

 these appeared later in the fresh blood and were the common type in the stale blood. 

 Habit (b), the tabular, crystals were also seen with the combination of habit (a), but 

 distinctly tabular. The crystals of habit (a) and these occasional crystals of habit (b), 

 which show the same planes, are distinctly clinohedral or domatic in form, that is, 

 hemimorphic on an axis normal to the ortho-axis. But habit (b), which appears to be 

 the normal form of crystal of the oxyhemoglobin, is only occasionally seen in these 

 clinohedral crystals. 



Homogeneous regular growths occur, the crystals having a common prism-basal- 

 pinacoid edge and uniting on the base (text figure 28) . This closely resembles the mica 

 twin. It appears, sometimes, to be repeated in irregular order and probably accounts 

 for anomalous extinction seen in a few large, apparently composite, crystals. Seen in 

 edge view the twin is readily recognized by the different extinction angles in the several 

 parts of the composite crystal (text figure 29) , which shows the twin in section, examined 

 along the axis a. 



a/ 



FIGS. 25, 26, 27, 28, 29. Python mobtrut a-Oxyhemoglobin. 



The color of the crystals is deep oxyhemoglobin red. Pleochroism is rather strong 

 in both habits of crystals when examined on the base, but not so noticeable on the edge 

 view, when the plates are examined, on account of the strong color in this aspect. The 

 pleochroism is best seen in the plates, because the dimensions of the rods are such that 

 the depth of color is influenced by the greater thickness of the crystals along a than 

 along 6. 



The pleochroic colors are: a yellowish-red, b deeper and somewhat blood-red, 

 c deep blood-red. Orientation of the elasticity axes is a A a = 21 in the obtuse angle, 

 b=6, c A 6=4 in the obtuse angle. The axial plane lies in the plane of symmetry, and 

 c=Bx a , the acute bisectrix. The optical character is hence positive. The interference 

 figure is seen on the base in the tabular crystals and shows the symmetrical extinction, 

 with a single brush of the figure in the field. The angle 2E could not be measured, but 

 was large; the other brush is out of the field. 



