TO SPECIES, ACCORDING TO PREVIOUS INVESTIGATORS. 133 



ability both vary according to the species of animal; but the investigations 

 undertaken in this direction suffer from so many and such large errors that 

 they prove nothing beyond what has long been known, that is, the different 

 species and individuals. " Preyer's statement that the form of the crystals 

 can not be altered by repeated recrystallization, and that there is a constant 

 and peculiar form in relation to each kind of animal, has been shown to be 

 wrong by the records of Halliburton (page 115), Copemann (page 119), von 

 Stein (page 127), Bonnel (page 129), Friboes (page 129), Moser (page 129), 

 and Pregl (page 130). 



The work of Preyer was so painstaking and exhaustive that his con- 

 clusions seem to have been accepted without question, and his dictum that 

 all hemoglobins crystallize in the orthorhombic system with an exception 

 which crystallizes in the hexagonal system seems to have absolutely dis- 

 couraged investigation in the crystallography of hemoglobin, and such 

 studies as have since been made have been chiefly with the view of dis- 

 tinguishing human blood from that of domesticated animals, for medico-legal 

 purposes. 



Of the papers treating of the crystallography of hemoglobin in rela- 

 tion to species from this standpoint, those of Guelfi (Giornal di Med. Legale, 

 1898; Maly's Jahr. ii. d. Fort. d. Thierchemie, 1898, 145) and Moser (Viertel- 

 jahr. ger. Med., 1901, xxn, 44) may here be noticed. Guelfi obtained " tetra- 

 hedral crystals" from guinea-pig's blood and "prismatic crystals" from 

 dog's blood, using both fresh and dried blood in each case. Comparing 

 these with crystals obtained from partly dried human blood, which crystals 

 he describes as "needle-shaped," he states that they can be distinguished 

 from each other so that "it can be definitely stated that neither the tetra- 

 hedra from the guinea-pig blood nor the prisms from the dog blood were 

 from human blood." 



Moser describes crystals obtained from the blood of about a dozen 

 species of vertebrates including mammals and fish. His article is illustrated 

 with drawings made from the appearances of the crystals under the micro- 

 scope, but these are not accompanied by any exact crystallographic descrip- 

 tions. The differences in the shapes of the crystals led him to the conclusion 

 that differences in the forms of the crystals afford a positive means of recog- 

 nition of the origin of the blood, and that in this way positive distinction 

 can be made between human blood and the blood of other animals. The 

 descriptions of the crystals are very brief and relate to their general mor- 

 phology; this is true also of the drawings. No correlation of the different 

 shapes of crystals found in the same species is attempted, and what are 

 evidently different views of the same crystal are shown as different forms. 

 It is obvious that he is distinguishing the different crystals merely and 

 hazardously by their morphology. Moser's article has been the subject of 

 adverse criticism, as will be pointed out. 



Various observers have studied the shapes of the ciystals obtained 

 from the bloods of different species, and in a few instances the crystal 

 system has been determined by crystallographic study, and from these 

 data they have arrived at the conclusion that the bloods of different species 



