134 CKYSTALLOGRAPHY OF HEMOGLOBIN IN RELATION 



may be distinguished by an examination of the hemoglobin crystals. On 

 the other hand, this conclusion has been contradicted by many observers. 

 Teichmann, for instance, as already stated, asserts that from the same blood, 

 and even from the same preparation, he has obtained various crystal forms, 

 and that still other forms may be produced by varying the method of prepa- 

 ration, from which he naturally concludes that the form of the crystal is 

 something entirely accidental and dependent upon exterior conditions and 

 not an essential character of hemoglobin. Others have made the observa- 

 tion that in the same blood several forms of crystals may be found. It 

 has also been pointed out that crystals from the blood of a given species, 

 as recorded by different investigators, are of different forms. Thus, Leh- 

 mann described the crystals from the guinea-pig as isometric tetrahedra, 

 he also describes them as isometric octahedra; Moleschott states that they 

 are 6-sided plates. Von Lang writes that they are only seemingly isometric, 

 and that, while the angle of the triangular face is so near 60 that they can 

 not be distinguished from isometric tetrahedra, the optical characters make 

 them orthorhombic. Donogany measured the three angles of the triangular 

 face of these crystals and records them as 6411', 6050', and 5545', which 

 three angles it will be noted do not add up to 180. Of course the explana- 

 tion of the record of tetrahedra in the one instance, of octahedra in another, 

 and of 6-sided plates in a third is veiy simple. All of these observers were 

 examining crystals of the same substance, and all were, as von Lang and 

 Donogdny state, orthorhombic sphenoidal: in the case of the simple "tetra- 

 hedra" the right or left sphenoid only was observed; in the case of the 

 "octahedra" the crystal was the combination of the right and left-handed 

 sphenoids in approximate equilibrium; and in the last instance, of the 6- 

 sided plates, the form seen was this combination observed normal to a 

 sphenoid face upon which the crystal is flattened, causing the outline to 

 be hexagonal. The outline of an octahedron looked at as it lies on one of 

 its faces is hexagonal, but if it become flattened parallel to the face upon 

 which it lies it appears at a casual glance to be a hexagonal plate. 



Many such cases as that of the guinea-pig crystals have been noted, 

 where the blood of the same species by varying the treatment, or even 

 according to different observers, furnished crystals of diverse form; and 

 many observers have been led to the conclusion that was reached by Teich- 

 mann, that the forms of hemoglobin crystals are variable in the same 

 species, are perhaps even identical in different species, and that the differ- 

 ences are not to be relied upon for distinguishing the source of the blood in 

 any given case. 



When the article by Moser appeared it apparently revived interest in 

 the subject of the differentiation of the crystals of different species, but his 

 results were soon attacked by Bonnel (These de Paris, 1903; Maly's Jahr. 

 ii. d. Fort. d. Thierchemie, 1903, xxni, 182) and by Friboes (Archiv f. ges. 

 Physiologie, 1903, xcvin, 434). Bonnel argued that because human blood 

 treated in the way described by Moser crystallizes in different shapes the 

 method is of no value. He points out that the method is not to be recom- 

 mended for the purpose of distinguishing human and animal blood (although 



