CRYSTALLOGRAPHY OF HEMOGLOBINS OF THE UNGULATES. 205 



prepared in the usual manner. Crystallization began in the protein ring 

 shortly after covering the slides, but soon after they formed these crystals 

 began to dissolve; due, no doubt, to the establishment of equilibrium 

 between the concentrated solution near the protein ring and the less con- 

 centrated solution throughout the slide. The crystals subsequently formed 

 mainly around the edge of the cover, owing to concentration of the solution 

 in that region, due to evaporation through the balsam seal. Crystals of 

 oxyhemoglobin, in the form of bipyramids, and of hemoglobin, in the form 

 of broad lath-shaped crystals, were developed side by side ; but the reduced 

 hemoglobin crystals began to appear later than those of oxyhemoglobin. 

 Both kinds of crystals were tested by the spectroscope. The crystals formed 

 practically at room temperature, although the slides were kept at a tem- 

 perature below 10. 



Oxyhemoglobin of Cervus dama. 



Tetragonal: Axial ratio a : 6 =1 : 1.200. 



Forms observed: Unit pyramid (111), traces of base (001). 



Angles: 111 A TTl =61, measured over the pole; the angle 

 of the pole edges, measured in the same way, was edge 111- 

 1T1 A 1T1-IT1 =79 (calculated 79 36') ; profile of pyramid look- 

 ing along <} gave 90 between the edges. 



Habit pyramidal (text figure 152), the unit pyramid in very 

 perfect development or with some faces larger, due to lying on the 

 slide; a few crystals seemed to show the base (001). The crystals \/ 152 



are very small, but well formed. In some cases they appeared like FIG. 152. Cmiu dama oxy- 

 skeleton crystals, due to some tendency to parallel growth appar- 

 ently; some formed interpenetrating groups resembling twins; in one or two cases these 

 appeared to be twins on the pole edge as twin axis. From the optical anomalies noted 

 in some crystals, they may be some form of a mimetic twin of the orthorhombic system, 

 with the groups producing tetragonal symmetry. The skeleton-like crystals mentioned 

 might be such interpenetrant orthorhombic twins. 



Pleochroism was not very strong, but the axis of greater elasticity was the axis of 

 less color. On the basal aspect, looking along 6, the crystals normally show single refrac- 

 tion, but the crystals presenting this aspect were too small to show an interference figure. 

 A few of them showed double refraction, not very strong, but extinguishing along the 

 two equal diagonals of the square section. This optical anomaly may indicate a twinned 

 orthorhombic structure. On the side views normal to 6, the extinction is parallel to the 

 vertical axis t in all aspects. The double refraction is fairly strong, the vertical axis 

 (i =e being the axis of greater elasticity. Hence w > s and the optical character is negative. 



Reduced Hemoglobin of Cervus dama. 



Probably orthorhombic, perhaps rnonoclinic; the crystals were very imperfect. 

 They showed sometimes a roughly four-sided cross-section, with an angle of perhaps 

 85, but most of them seemed to be rather lath-shaped. They were generally not ter- 

 minated; a few showed square-cut ends, but the majority were merely shred-like masses, 

 with more or less straight sides and splintery looking ends. They were also in spheru- 

 litic masses and are probably parallel or radiating groups of smaller prisms; the parallel 

 groups forming the prism-like shreddy crystals and the radiating groups the spherulites 

 and tufts of crystals. The parallel masses show straight extinction, the spherulites 

 extinguish parallel to the fibers and show the usual extinction cross of spherulitic masses 

 of crystals in polarized light. The straight groups of crystals show the length of the 

 prisms to be the direction of greater elasticity and the direction normal to this to be the 



