200 CRYSTALLOGRAPHY OF HEMOGLOBINS OF THE UNGULATES. 



to crystallize soon after putting the covers on the slides, and the crystals 

 continue to improve for about 2 hours, after which they begin to dissolve 

 in the serum, becoming porous and losing their form. This breaking down 

 of the crystals takes place first in thin preparations and is very likely due 

 to an increase of pressure on the liquid of the preparation owing to the 

 hardening of the balsam seal of the slide. In the thicker slides, with a thick 

 layer of serum, the crystals do not show the same tendency to dissolve as 

 they do in the thinner preparations. Inside of 24 hours the crystals of 

 reduced hemoglobin begin to make their appearance, along with isolated 

 crystals of the oxyhemoglobin, which latter are rather better formed than 

 those observed within a couple of hours of first making the preparation. 



Oxyhemoglobin of Domesticated Variety of Sus scrofa. 



Orthorhombic: a : b : 6 =0.6248 : 1 : 0.6008. 

 Forms observed: Unit prism (110), unit brachydome (Oil). 

 Angles: 110 A lTO=64 (normals) ; Oil A Oil =62 (normals). 

 Habit short prismatic, nearly equidimensional or somewhat 

 elongated vertically (text figure 141) ; sometimes distorted, by elon- 

 gation parallel to two parallel dome faces along an axis lying in the 

 macropinacoid, and then having a monoclinic aspect. Twinning 

 was not observed, and the crystals usually occurred singly. 



Pleochroism is hardly noticeable when looking along a, but in 

 the plane of a and c or a and & it is readily observed; a is very pale 

 yellowish-red; b is deep scarlet-red; c is about same color. Extinc- 

 gio'bin.* 5 tion is straight or symmetrical in all aspects, but looking along a the 



double refraction is very weak. The axial plane is the basal pina- 

 coid and the orientation of the elasticity axes is a=a, b=c, c=b; absorption c > b > a. 

 From the double refraction and the pleochroism, as well as from the absorption, which 

 show c and b to be nearly equal, it would seem that the acute bisectrix Bx a = a, and the 

 optical character is negative. 



Reduced Hemoglobin of Sus scrofa, Domesticated Variety. 



In the slides after standing for 24 hours there always developed numerous long 

 prismatic crystals of reduced hemoglobin, which appear at first around the margin of the 

 cover, and later throughout the body of the slides. They show straight extinction on 

 most aspects, but have a decidedly monoclinic habit, being terminated obliquely in many 

 cases. Some appeared to have square ends; others, a single plane like a basal pinacoid, 

 but oblique. They appear to be monoclinic. They grow in tufts and in sheaf-like aggre- 

 gates, sometimes even in feathery groups. They appear to twin on a dome or pyramid, 

 and also on the prism. The terminal plane is usually very imperfect, due to a fibrous 

 character which the crystals show, the ends of the fibers making a rough plane. Smaller 

 crystals and short stout prisms show a very monoclinic aspect. 



Muis DEER OR CHEVROTAIN, Tragulus meminna. Plate 34. 



The specimen was obtained from the post mortem of an animal that 

 died in the Philadelphia Zoological Gardens. The blood was oxalated, 

 ether-laked, and centrifugalized; the slides were prepared in the usual 

 manner. Crystals formed readily and did not show a tendency to dissolve 

 on bringing them into a warm room. They were oxyhemoglobin. Later, 

 the same slides developed crystals of reduced hemoglobin, along with those 

 of the oxyhemoglobin; these latter being relatively enormous. Both kinds 

 of crystals were very sharp and well defined. 



