182 W. D. HALLIBURTON. 



1. Historical. 



Oxyhemoglobin crystals were first described by Reichert 1 as 

 occurring in the uterus of a pregnant guinea-pig ; by Leydig 2 

 as occurring in the alimentary canal of the leech ; and by 

 Kolliker, 3 obtained from the blood of the dog, python, and 

 other animals. Kolliker considered the crystals to be com- 

 posed of a more or less modified hsematin. Funke 4 was, how- 

 ever, the first to make complete observations upon them, and 

 to recognise their true nature. Kunde, 5 working at the same 

 time, made extensive observations from a comparative point of 

 view, and was the discoverer of the exceptional form of the 

 crystals in the guinea-pig and squirrel. Since then many 

 investigators have worked at the subject, notably Lehmann, 6 

 Rollett, 7 von Lang, 8 and Preyer, 9 in whose exhaustive treatise 

 a complete bibliography of the subject up to 1871 is given. 



Our present knowledge of the crystalline form that haemo- 

 globin assumes may now be summarised as follows: 



a. In the great majority of animals 10 in which haemoglobin 



1 Reichert, « Miiller's Archiv,' 1849, p. 197. 



2 Leydig, ' Zeitsch. f. wiss. Zool.,' Bd. i, 1849, p. 116. 



3 Kolliker, ' Zeitscb. f. wiss. Zool.,' Bd. i, 1849, p. 266. 



4 Funcke, 'Zeitsch. f. nat. Med.,' N. F., Bd. i, 1851, p. 184; Bd. ii, 

 1852, p. 204 and p. 288. " De sanguine venae lievates," 'Diss. Lipsise," 

 1851. 



5 Kunde, ' Zeitsch. f. nat. Med.,' N. F., Bd. ii, 1852, p. 276. 



6 Lehmann, ' Ber. d. k. Sach's Ges. d. Wissen.,' 1852, p. 22. 



7 Bollett, ' Sitzungsber. d. Wien. Akad./ Bd. xlvi, 1862, p. 65. 



8 Lang, ibid. 



9 Preyer, ' Die Blutkrystalle,' Jena, 1871. 



10 To the animals falling under this rule I can add several, the crystalline 

 form of the haemoglobin of which have not been hitherto recorded. I am 

 much indebted for specimens of the blood of these animals to my friend 

 Mr. F. E. Beddard, of the Zoological Gardens. 



Opossum (Didelphys cancrivora). — Very large and dark red crystals, 

 can be readily obtained. They belong to the rhombic system. 



Kangaroo (Macropus giganteus). — Crystals are more soluble, and 

 so less readily obtained. They are rhombic prisms, slenderer than in the 

 opossum. 



