CRYSTALLOGRAPHY OF HEMOGLOBINS OF THE UNGULATES. 



203 



Habit bipyramidal (text figure 148); also combinations of the diametral prism 

 with the unit pyramid (text figure 149) ; these latter occur more rarely. The crystals 

 were usually single and isolated; but in some cases formed irregular linear aggregates, 

 straight or curved, some being evidently parallel growths. Twinning on the unit pyra- 

 mid, as the plane of twinning, was observed, but was not common; the twins are pene- 

 tration twins, but otherwise resemble the spinel twins somewhat (text figure 150). 



150 



Flos. 148, 149, 150. Cervia canadennt Oxyhemoglobin. 



The color was oxyhemoglobin red and the pleochroism is not very marked; absorp- 

 tion for a) greater than for s. The double refraction is not very strong, showing better 

 in the prismatic crystals; extinction is parallel to the vertical axis c, which is the axis 

 of greater elasticity. On the square sections, looking along the polar axis, the crystals 

 are singly refracting and do not polarize; and in convergent light they show a uniaxial 

 figure in the shape of a dusky cross. The optical character is negative, u> > e. 



RED-BACKED DEER (PROBABLY THE RED BROCKET, Cariacus rufus). Plate 35. 



The specimen of blood was received from the Philadelphia Zoological 

 Gardens, and was beginning to putrefy. It was treated by oxalating and 

 freezing, then laked with ether and centrifugalized. The slides were pre- 

 pared in the usual manner and kept at a temperature near the freezing-point. 

 It crystallized readily, the crystals that were the first to form being long 

 lath-shaped rods ; these were followed by large rectangular plates, very thin, 

 and evidently the same as the rods, but of a tabular habit. When the slides 

 were brought into a warm room the plates were rapidly dissolved ; the rods 

 showed more resistance to solution, but it was found necessary to examine 

 the slides in the cold, and all photographs were taken at a temperature near 

 the freezing-point. The crystals gave the spectrum of reduced hemoglobin. 



Reduced Hemoglobin of Cariacus rufus. 



Monoclinic: Axial ratio could not be determined, as only pinacoids were seen. 

 Angle p appears to be about 90. 



Forms observed: Base (001), clinopinacoid (010), orthopinacoid (100). 



Angles: Clinopinacoid to orthopinacoid, the outline of the plates, 010 A 100=90; 

 base to orthopinacoid, angle /?, about 90, perhaps exactly 90. The third angle was 

 not observed, but must be 90 in this system. 



Habit lath-shaped crystals elongated on the clino-axis, and flattened on the base; 

 these, by elongation on the ortho-axis also, became rectangular plates, which are fre- 

 quently as long as the lath-shaped rods and perhaps 30 times as wide. The plates appear 

 to be produced by the piling up of narrow plates all in parallel position and this produces 

 striation on most of these plates parallel to the a axis. The rods grow in tufts, radiating 

 or brush-like, generally united with each other on the base, or in the zone of (OOl)-(lOO). 

 The composite plates are produced in the same way, by uniting on the base. No definite 

 twinning was observed, but possibly the piled-up plates may be polysynthetic twins. 



