254 



CRYSTALLOGRAPHY OF THE HEMOGLOBINS OF THE 



formed readily at room temperature, about as readily as in the case of the 

 dogs. Within 3 hours after covering, satisfactory negatives of the crystals 

 were secured. The tabular crystals at first formed showed a slight tendency 

 to dissolve in the solution when brought into a warm room; but when kept 

 in the cold they were permanent for more than two weeks. After about 3 

 days in the cold, long rod-like crystals made their appearance; these 

 appeared to be more soluble than the tabular crystals and dissolved when 

 brought into the warm room. These large rods were not so permanent as 

 the tabular crystals, and inside of 2 weeks had almost entirely disappeared 

 from the slides; but smaller crystals of the prismatic type were still to be 

 seen in the slides at the end of 15 days. The crystals were oxyhemoglobin, 

 as shown by the microspectroscope ; crystals of reduced hemoglobin were 

 not observed. 



55 



Oxyhemoglobin of Taxidea americana. 



Monoclinic: Axial ratio a : b : 6 = 1.0355 : 1 : 1.0125; /? = 54 32' (calculated, or 

 measured). 



Forms observed: Unit prism (110), positive hemiorthodome (101), base (001), 

 orthoprism (430). 



Angles: Unit prism, traces on the base, or edges 110-001 A 110-001=88; macro- 

 prism edges on base 430-001 A 530-001=75 30' (calculated 75 24'); actual angle of 

 unit prism 110 A 110 = 76 20'; positive hemiorthodome on base 10T A 001=61 30'; 

 prism edge on base or angle /? = 54 32' (calculated, or 55 measured). 



275 



Flos. 269, 270, 271, 272, 273, 274, 275. Taxidea americana Oxyhemoglobin. 



The crystals occur in two habits which may be designated as type (a) and type (b) ; 

 type (a) crystals are the first to appear. 



Crystals of type (a) : Habit at first tabular on the base and appearing as five-sided 

 plates, consisting of the unit prism and base with one face of the unit positive hemiortho- 

 dome (T01) (text figures 269 and 270), which gives the crystal a strongly clinohedral 

 form. These crystals grow in thickness by elongation of the prism, and the other face 

 of the hemiorthodome (10T) appears by the time they become nearly equidimensional; 



