CHAPTER V. 



THE INVESTIGATIONS OF PREYER ON THE CRYSTALLOGRAPHY 



OF HEMOGLOBIN. 



The monograph of Preyer (Die Blutkrystalle, Jena, 1871, 263 pages, 

 3 plates) , which continues to the present day to be the leading authority on 

 the crystallography of hemoglobin, had for its foundation several contribu- 

 tions that were published a few years previously, and which were chiefly 

 with reference to the optical and chemical properties of hemoglobin. His 

 first serious contribution to the crystallography of hemoglobin appeared 

 in 1868 (Archiv f. ges. Physiologic, 1868, i, 395), in which he expresses his 

 surprise that so little is known of hemoglobin. He writes that while blood 

 crystals have been obtained from 47 vertebrates (23 mammals, 7 birds, 4 

 reptiles, 1 amphibian, and 12 fishes), in only 10 of these was the crystal 

 system ascertained. The crystals of the human being, the dog, the guinea- 

 pig, and the rabbit were found by von Lang to be rhombic; those of the 

 cat according to Rollett, those of the horse according to Funke, and those 

 of the lion, jaguar, and marbled cat according to Preyer, are also rhombic; 

 while those of the squirrel, according to von Lang, are hexagonal. Preyer 

 goes on to state that in addition to those mentioned the following are prob- 

 ably rhombic: those of the monkey, bat, hedgehog, sheep, pig, harfang 

 (owl), and frog. The blood of the monkey yielded rhombic plates which 

 crystallized with difficulty and which were readily soluble, even in the cold. 

 The blood of the bat crystallized in thin plates with very pointed angles. 

 Hedgehog blood produced right-angled elongated prisms, which even in 

 the cold are readily soluble. Sheep's blood crystals were obtained only 

 once in gas-free blood, and they were prisms. Pig's blood crystallized with 

 extraordinary difficulty, mostly intraglobular (in every corpuscle a prism). 

 The blood of the harfang (Strix noctua) crystallized readily, but that of the 

 frog with difficulty. The former yielded 4-sided plates; the latter, thin 

 prisms, which appeared to be 4-sided. Of the other blood crystals pre- 

 viously seen, those of the mouse and the hamster, he states, might be hex- 

 agonal. Preyer obtained from the blood from the heart of a mouse only 

 fine needles. The hemoglobin crystals of the fox, polecat, mole, marmot, 

 ox, raven, sparrow, pigeon, goose, duck, lark, rat, and fish were produced, 

 but their crystallographic investigation gave little satisfaction; most of 

 them appeared to be rhombic. 



Preyer, in his review, writes that Lehmann's statement that occasion- 

 ally regular octahedrons are found in guinea-pig blood is incorrect; and also 

 that Hoppe-Seyler's assertion that guinea-pig blood crystals are tetragonal 

 is wrong. He also states that the opinion of Funke that human and cat 



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