116 



PREPARATION AND CRYSTALLOGRAPHY OF HEMOGLOBINS 



inherent in the hemoglobin, he in some instances mixed serum, or the 

 serum and the stromata, or the blood of one species of animal with the 

 blood of another, or solutions of hemoglobins of different species with one 

 another. 



The presence of the foreign serum, or serum and stromata, was without 

 influence on crystalline form, and, while mixed bloods, or mixed hemoglobin 

 solutions, did not affect crystalline form, they sometimes caused modifica- 

 tions in crystalline habit. Thus, in case of the bloods or solutions of hemo- 

 globins of the rat and guinea-pig the crystals of the rat were rhombic with 

 hexagonal habit, no needles or tetrahedra being present. (See table 33.) 



TABLE 33. Forms of hemoglobin crystals in case of mixed bloods 

 (from Halliburton). 



Blood of 



Mixed with that of 



Rat. 



Rat. 



Squirrel. 



Dog.. 

 Dog. 



Squirrel. . 

 Guinea-pig. 



Guinea-pig. 



Form of hemoglobin crystals from the mixture. 



Squirrel. . . . 

 Guinea-pig. 



Both rhombic prisms and hexagons 

 present. 



No rhombic prisms of the shape usu- 

 ally seen in rat's blood present. No 

 tetrahedra. Crystals are all rhom- 

 bic prisms with hexagonal habit. 



Hexagonal plates and tetrahedra both 

 present. Many tetrahedra imper- 

 fect. The tetrahedra were all re- 

 duced to about half the size of those 

 prepared from the unmixed blood of 

 the same guinea-pigs. 



Fine rhombic needles and hexagonal 

 plates both present in abundance. 



The greater number of the crystals 

 formed are very small tetrahedra, 

 about a quarter the size of those 

 prepared from the blood of the same 

 guinea-pigs. The optical properties 

 are, however, the same. Rhombic 

 prisms very slender, like those of 

 dog's blood, also seen. 



In another set of experiments Halliburton tried to break down the 

 hexagonal constitution of the hemoglobin of squirrel's blood, first, by draw- 

 ing off the water of crystallization and then adding water; second, by 

 converting the hemoglobin into methemoglobin, and then by reducing 

 agents to form once more hemoglobin, and to obtain crystals from this. 

 Both attempts were unsuccessful. 



In opposition to the statement of Preyer that recrystallization does 

 not alter the form of the crystals, Halliburton found that by recrystalliza- 

 tion of squirrel's hemoglobin, after 3 or 4 recrystallizations no 6-sided 

 crystals were obtained, but a mixture of rhombic needles and tetrahedra, 

 and that in some cases the latter were absent. In conclusion, the author 

 states that the difference between the various forms of hemoglobin can not 

 be a very deep or essential one, and that it seems to narrow itself down to 

 this, either we have a case of polymorphism or the cny-stalline forms are due 

 to the combination with varying proportions of water of crystallization. 



