186 HAEMOGLOBIN. 
composition, according to the species of animal from which it has 
been derived. Based upon these facts, or perhaps in order to emphasise 
them, it is now customary with German writers, following the example 
of Hoppe-Seyler, to speak, not of " oxyhemoglobin," but of " the 
oxyhemoglobins," of "the haemoglobins " and not of "hemoglobin." 
This appears to me to be aii unnecessary and misleading attempt to 
attain accuracy in scientific terminology, at the expense of true and 
philosophical conceptions. As will be shown in the sequel, the 
proportion in which iron, the characteristic element in the blood- 
colouring matter, occurs; is absolutely the same in many animals, the 
weight of the molecule being probably identical in these cases. There 
is further abundant evidence in favour of the view that the typical 
nucleus, upon which the optical and physiological properties of hemo- 
globin depend, is absolutely identical in all animals. The grounds 
for this assertion will be given in the sequel, when it will be shown 
that the opinion advanced of recent years, as to the existence of 
several hemoglobins, not only varying in composition, but possessed 
of different powers of combining with oxygen, rests upon undoubted 
fallacies. 
Distribution of Haemoglobin throughout the Animal Kingdom. 
After the discovery by Hoppe-Seyler x of the characteristic spectrum of 
haemoglobin had enabled him definitely to prove that this substance is the 
true blood-colouring matter, Kuhne 2 showed that the same body is the cause 
of the red colour of the voluntary muscles of vertebrates. Hunefeld 3 and 
Rollett i bad shown that the blood of the earth-worm and of Chironmous 
yielded crystals identical with the blood crystals obtained from other animals ; 
and Kay Lankester 5 and Nawrocki 6 simultaneously established the fact that 
these crystals consisted of haemoglobin, by examining their spectroscopic 
characters. 
In a series of researches, which extended from 1867 to 1872, Lankester 
investigated the distribution of haemoglobin throughout the animal kingdom, 
and comparatively few facts have since been added to those which he 
published in 1^7l'. 7 
The following are among the principal facts hitherto ascertained in rela- 
tion to the distribution of haemoglobin. 15 
Haemoglobin occurs : — 
1. In special corpuscles — 
(a) In the blood of all vertebrates, excepting LeptocephcUus and Amphioxus. 
1 Felix Hoppe in Tubingen, "Ueber das Verhalten des Blutfarbstoffes im Spectrum 
des Sonnenlichtes," Virchow's Archiv, 1862, Bd. xxiii. S. 44f5-44i' : ■"Ueber die cheuii- 
scben u. optischen Eigenschaften des Blutfarbstoffs," Virchow's Archiv, 1864, Bd. xxix. 
S. 233-245. 
2 " Ueber den Farbstoff der Muskeln," Virchow's Archiv, 1865, Bd. xxxiii. S. 79; 
Kuhne, "Lehrbuch d. phys. Chemie," 186S, S. 288. 
3 "Das Blut der Regenwiirmer," Joitrn./. vrakt. Chan., Leipzig, 1839, Bd. xvi. S. 152. 
4 " Ziir Kenntniss der VerbreitungdesHsematins," Sitzungsb. d. k. Akad. d. JVissensch., 
Wien, 1861, Bd. xliv. S. 615-630. 
3 " Observations with the Spectroscope," Joum. Anat. and Physiol., London, 1867, 
S. 114. 
6 "Optische Eigenschaften des Blutfarbstoffs," Centralbl. f. J. med. JVissensch., Berlin, 
1867, S. 196. 
7 "A Contribution to the Knowledge of Haemoglobin," Proc. Roy. S'oc. London, 1872, 
vol. xxi. pp. 70-81. 
8 The student is advised to read the interesting chapter, entitled "The Blood of 
Invertebrate Animals,'' in Halliburton's Text-Book, see pp. 316-330. 
