CRYSTALLOGRAPHY OF HEMOGLOBINS OF THE UNGULATES. 



213 



in the usual way, yielding a small amount of clear solution, from which 

 slide preparations were made as usual. The blood began to crystallize 

 in needles soon after the preparations were covered. These formed in 

 the protein ring, but afterwards dissolved as the solution under the cover 

 came to an equilibrium, while new rod-like and tabular crystals appeared 

 throughout the slides. These crystals seemed to be not very soluble, al- 

 though rise of temperature caused a loss of the planes on the ends of the 

 long lath-shaped crystals; and with the oxyhemoglobin crystals were mixed 

 occasional crystals of reduced hemoglobin. The absorption spectra of both 

 kinds of crystals were examined by the microspectroscope. The photo- 

 graphs were made 3 days and 5 days after the preparation of the slides. 



Oxyhemoglobin of Ovis nahura. 



Monoclinic: Axial ratio a : b : I =1.232 : 1 : <5; /?=54 15'. 



Forms observed: Unit prism (110), base (001), orthopinacoid (100), clinopinacoid 

 (010), hemiorthodome (101). 



Angles: Plane angle of base on prism, edges 110-001 A 110-001=63 (angle of 

 termination of the flattened prisms), orthopinacoid to base 100 A 001 =/? = 54 15'; 

 angle over edges of pentagonal twin 71 30' (normals). 



-b 



169 



\ 



173 



FIGB. 169, 170, 171. Ovit nahura Oxyhemoglobin. Flos. 172, 173. Ovit nahura Reduced Hemoglobin. 



Habit prismatic, elongated on the vertical axis, forming prisms with the ends 

 terminated obliquely by the base (text figure 169), the plane angle of the trace of the 

 base on the prism being about 83, but not exactly determined; also in lath-shaped 

 crystals, by flattening on two opposite prism faces, the ends then terminated by the 

 oblique plane of the base producing a triclinic aspect (text figure 170) ; and in this form 

 often with the prism so shortened that the rhombic plates appear to be triclinic tables 

 with plane angles of 63. Twins on the flattened prism, resembling carlsbad twins (text 

 figure 171), rather rare; also commonly twins on the orthopinacoid and on the hemi- 

 orthodome as in sheep (text figure 166). This second kind of twinning forms both pentag- 

 onal groups, as in sheep, and also networks of rod-like crystals, this latter perhaps by 

 twinning on the base instead of the orthopinacoid (see plate 43) . The little pentagonal 

 groups grow attached to the long prism-like crystals, as in the sheep crystals, and produce 

 a cross-barred effect upon the orthopinacoid surfaces, due to the strong pleochroism. 

 The crystals strongly resemble those of the sheep in these twins, but the prismatic habit is 

 different. A third kind of twinning on a prism, producing an X-shaped interpenetrant twin, 

 was seen, but it occurred very rarely. The pentagonal twins are much more irregular than 

 in the sheep crystals; and they show usually a skeleton form, instead of even-sided pen- 

 tagons, due to parallel growth. The description of this twin will be found under Sheep. 



