OF THE LEMURS, BABOONS, AND MAN. 



317 



larger than the other and giving a rather unsymmetrical aspect to the crystal (text figure 

 404) . Twins of the horse-type are rather common (text figure 405) ; but, as the plates are 

 thick, the twin does not have the usual appearance. It is often seen in edge view only; 

 when seen on the flat, it is usually more obviously an overlap than in the case of the horse. 

 Pleochroism is strong; a colorless, b deep red, about the color of the plasma in a 

 moderately thick slide ; c deep red, of a deeper shade than the plasma. Double refraction 

 is strong in all ordinary aspects. Orientation of the elasticity axes is a A a = 13, in the 

 obtuse angle; 6=6; c A ^=5 30', in the obtuse angle. On the base, in convergent 

 light, an interference figure is seen, with the optic axes lying in the plane of symmetry. 

 The acute bisectrix is the axis of least elasticity, Bx a = c, and the optical character is 

 hence positive. The angle of the optic axes is wide, 2E =75 to 80. Dispersion of the 

 optic axes is red > violet. 



jr-Oxyhemoglobin of Papio anubis. 



Orthorhombic: Axial ratio a : b : 6 =0.3268 : 1 : t. 



Forms observed: Unit prism (110), base (001). 



Angles: Prism angle 110 A 1TO=36 12' average; 

 prism to base 110 A 001=90. 



These crystals appeared as a "second crop" about 

 three days after the first preparations were made. Habit 

 thin tabular, consisting of the very oblique prism cut by the 

 base (text figures 406 and 407), and with a thickness of 

 plate of one-fifteenth to one-twentieth of the length of 

 the 6-axis. The crystals grow in tufts, often radiating, and 

 occasionally are seen isolated; they are very thin and show scarcely any difference 

 in the color from the solution when viewing a single crystal on the basal aspect. 

 They do not appear to twin. They developed usually around the edge of the protein ring. 



On account of the thinness of the plates, pleochroism is not very noticeable on the 

 basal aspect, on edge view it is stronger; the colors are shades of the OHb red, with a 

 the palest color and c the deepest. Double refraction is easily noted and extinction is 

 straight on the edge view and symmetrical on the base. The orientation of the optic 

 axes is fl = 6; b = o; c = <i. The plane of the optic axes is the macropinacoid. In con- 

 vergent light no definite interference figure could be observed in the basal aspect, which 

 was the only observable direction. It would appear probable, therefore, that the acute 

 bisectrix is the axis of greatest elasticity, Bx a = a, and the optical character is negative. 



TABLE 49. ft-Oxyhemoglobins of the baboons, genus Papio; monoclinic. 



407 



FIGS. 406, 407. Papio anubit Y-Oxy- 

 hemoglobin. 



MAN, Homo sapiens africanus. 



The specimen in which crystals of oxyhemoglobin were successfully 

 developed was from a negro woman. The blood was clotted, being obtained 

 from an afterbirth. The clot was ground in sand and etherized, then centri- 

 fugalized and treated as usual. The drops were evaporated until granular 

 oxyhemoglobin formed in the protein ring; and then, after covering, set 

 aside in the cold to crystallize. Crystallization began after 24 hours in the 



