CRYSTALLOGRAPHY OF HEMOGLOBINS OF THE UNGULATES. 199 



Color deep blood-red, pleochroism weak ; the shade of red is somewhat paler when 

 the light is vibrating parallel to s=6, which is the axis of greater elasticity. Extinction 

 is straight on all side views, normal to the t axis; and looking along 6 the crystal shows 

 only single refraction; it does not polarize. The refractive index of the extraordinary 

 ray s is less than that of the ordinary, s < 10, and hence the optical character is negative. 



137 



Fio. 137. Dicoiylet labialus Oxyhemoglobin. FIGS. 138, 139, 140. Dicotylts tajacu Oxyhemoglobin. 



COLLARED PECCARY, Dicolyles tajacu. Plate 32. 



The specimen was received from the Philadelphia Zoological Gardens. 

 The blood was quite putrid. It was laked with ether and centrifugalized, 

 and the slides prepared in the usual manner. Crystallization proceeded 

 rapidly, after the slides were covered, and they soon became filled with 

 small octahedra, apparently of the tetragonal system. They did not keep 

 well, and inside of 24 hours many of them were broken down. They did 

 not seem to be dissolved, but rather to be decomposed. They appeared to 

 be soft, as is the case with the first-formed crystals from the blood of the 

 common swine. The spectroscope showed that these crystals were oxy- 

 hemoglobin. 



Oxyhemoglobin of Dicotyles tajacu. 



Tetragonal: Axial ratio a : c =1 : 1.303. 



Forms observed: Unit pyramid (111), diametral prism (100), base (001). 



Angles of the pole edges of the pyramid =73; 111 A TTl=55, measured over 

 the pole. The crystals were so small that the faces (100) and (001) could not be measured. 

 Edges of the pyramid, in the horizontal plane, make an angle of 90 with each other. 



Habit octahedral or pyramidal, usually the unit pyramid alone, very symmetrically 

 developed (text figure 138) ; but some larger crystals show the base and some show the 

 diametral prism (text figure 139); what appears to be twinning was observed in these 

 crystals, the twinning plane a pyramid face and the twin an interpenetrant one analo- 

 gous to the spinel twin (text figure 140). 



Pleochroism is practically nothing, and the double refraction in aspects normal to 

 the tetragonal axis is weak; looking along the axis, on the square sections, the crystals 

 show no double refraction. 



PIG, DOMESTICATED VARIETY OF Sus scrofa. Plates 32 and 33. 



Fresh blood, defibrinated by beating, was centrifugalized and the 

 corpuscles alone used for the preparations. The corpuscles, from which 

 the supernatant serum had been drawn off with a pipette, were ether- 

 laked and again centrifugalized; then the clear liquid was saturated with 

 oxalate, and the preparations made in the usual manner. The blood begins 



