180 



CRYSTALLOGRAPHY OF THE HEMOGLOBINS 



Oxy hemoglobin of Sarcophilus ursinus. 



Monoclinic: Axial ratio a : b : 6 =1.804 :!:<!; /3=69 (111). 



Forms observed: Prism (110), base (001), clinopinacoid (010); also in twins (Til) 

 a positive hemipyramid, of which the angle was not determined. 



Angles: Traces of prism on the base, edge 110-001 A 110-001=58 (122); edge 

 of 110-lTO A 001=/3 = 69 (111). 



Habit prismatic, also tabular; the first crystals to appear are usually long thin 

 prisms and also shorter prisms with the length varying from 20 times to 6 times the 

 thickness (text figure 71); later nearly equidimensional blocks appear, short prisms 

 with ratio of length to thickness varying from 2 : 1 to 1 : 2 (text figure 72) ; finally a 

 few crystals become tabular on the base, with the prism reduced to perhaps one-tenth 

 of the thickness or width of plate (text figures 73 and 74). Twinning was observed with 

 the plane of twinning and composition plane the prism face (twin on the prism), both 

 contact (text figure 75) and interpenetrant (text figure 76) twins; also long prisms 

 twinned on a positive hemipyramid, of which the angle was not determined, called (Til), 

 as the plane of twinning and the twinning axis normal to this plane; these were inter- 

 penetrant twins. 



n\ 



7i 



7". 



If, 



FIGS. 71, 72, 73, 74, 75, 76. Sarcophilug urginua Oxyhemoglobin. 



Pleochroism strong; a pale yellowish, nearly colorless; b red, c deep red. Extinc- 

 tion is symmetrical on the base in the plates and all sections in zone of b; on side view, 

 on (010) the extinction is oblique with an extinction angle of 10 from the prism edge, 

 or 11 from the trace of the base (001). The axial plane is the plane of symmetry (010) 

 and the orientation of the elasticity axes is c A t = 10 lying in the obtuse angle ; a A a = 

 11 in the obtuse angle; b=b. The interference figure is seen on this basal section, with 

 the brushes slightly unsymmetrical and rather widely separated. 2E = above 80, and 

 the angle between c and the normal of (001) is 11. The acute bisectrix, Bx a = t, and 

 the optical character is hence positive. 



SPOTTED DASYURE, Dasyurus maculatus. Plate 18. 



The blood as received was thick and dark colored, somewhat putrid. 

 It was prepared by oxalating and freezing and thawing, then centrifugaliz- 

 ing. The best crystals were obtained by diluting the centrifugalized blood 

 with an equal volume of water. The needle-like, prismatic crystals appeared 

 soon after making the preparations. After 48 hours the crystals had 

 developed into large plates. The crystals were all reduced hemoglobin, 

 and even in ordinary light varied much in color, owing to the strong 

 pleochroism. 



