CRYSTALLOGRAPHY OF THE HEMOGLOBINS OF AVES. 167 



Oxyhemoglobin of Numida meleagris. 



Orthorhombic : Axial ratio a : b : 6 =0.554 : 1 : 6. 



Forms observed: Prism (110), base (001); and, in twins, unit pyramid (111). 



Angles: 110 A lTO=58 (normals); 110 A 001 =90. The angle of the prism 

 sometimes appears to approximate 60, but ran down as low as 57, and 58 seems to 

 be the best measurement. 





44 



"Tb 



Fios. 44, 45, 46. NumiJa meleaffrii Oxyhemoglobin. 



Habit thin to thick tabular; the rhombic plates varying in thickness from one- 

 tenth to one-fourth of the long diagonal of the prism; the crystals consist simply of the 

 short prism (110) and the base (001) (text figures 44 and 45). Twinning on the normal 

 to the prism-base edge as twin axis (horse-type) common (text figure 46) ; also twins 

 on the pyramid and perhaps a macrodome were observed. The crystals usually occur 

 singly or in twins, not in more complicated groupings. 



Pleochroism strong; a very pale yellow-red, b moderately deep scarlet-red, c very 

 deep red. Extinction on the base is symmetrical and on edge is straight in all positions. 

 The plane of the optic axes is the macropinacoid; the orientation of the elasticity axes 

 is a=6, b=a, c=(S. On the base, in convergent light, the biaxial interference figure is 

 seen with the axes rather widely separated; hence Bx a = t and the optical character 

 is positive. 



CARRIER PIGEON, Columba livia var. Plate 13. 



The bird was killed and bled and the blood allowed to form a clot. 

 This clot was then ground in sand, with excess of ether, and the mixture 

 centrifugalized ; afterwards 2 per cent of ammonium oxalate was added 

 and the preparations made as usual. Crystals began to form in about 2 

 hours. These crystals were Oxyhemoglobin, and formed only in the cold. 

 When taken into a warm room they melted rapidly. Another preparation 

 with and without oxalate was tried, but crystals did not form except when 

 the oxalate was present. 



In the slides from the first preparation containing the a-oxyhemoglobin 

 crystals (crystal a) there was formed after some days a second crop of 

 crystals (crystal 6) of metoxyhemoglobin and the a-crystals changed to 

 methemoglobin by paramorphism. The solution meanwhile had changed 

 to reduced hemoglobin as shown by the spectroscope, and finally needle- 

 like crystals of reduced hemoglobin (crystal c) appeared in the slides. By 

 the time that the reduced-hemoglobin crystals had formed, the 6-crystals 

 were converted by paramorphous change into pure methemoglobin. The 

 Oxyhemoglobin and the metoxyhemoglobin also were both converted into 

 pure methemoglobin in the presence of an increasing amount of reduced 

 hemoglobin. 



