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 " oxyhsemoglobin," but of " the 

 oxyhgemoglobins," of " the haemoglobins " and not of " haBmoglobin." 

 This appears to me to be an 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 haemo- 

 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 haemoglobins, not only varying in composition, but possessed 

 of different powers of combining with oxygen, rests upon undoubted 

 fallacies. 



DISTRIBUTION OF HEMOGLOBIN THROUGHOUT THE ANIMAL KINGDOM. 



After the discovery by Hoppe-Seyler l of the characteristic spectrum of 

 haemoglobin had enabled him definitely to prove that this substance is the 

 true blood-colouring matter, Kiihne 2 showed that the same body is the cause 

 of the red colour of the voluntary muscles of vertebrates. Hunefeld 3 and 

 Rollett * had 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 1872. 7 



The following are among the principal facts hitherto ascertained in rela- 

 tion to the distribution of haemoglobin. 8 



Haemoglobin occurs : 



1. In special corpuscles 



(a) In the blood of all vertebrates, excepting Leptoceplialus and Amphioxus. 



1 Felix Hoppe in Tubingen, "Ueber das A r erhalten des Blutfarbstoffes im Spectrum 

 des Sonnenlichtes," Vircliows Archiv, 1862, 13d. xxiii. S. 446-449 ; "Ueber die chenii- 

 sclien 11. optischen Eigenschaften des BlutfarbstolFs, " Virchow's Archiv, 1864, Bd. xxix. 

 S. 233-245. 



2 "Ueber den Farbstoff der Muskeln," Virchow's Archiv, 1865, Bd. xxxiii. S. 79; 

 Kiihne, " Lehrbuch d. phys. Chemie," 1868, S. 288. 



3 " Das Bint der Regenwiirmer, " Journ. f. prakt. Chem., Leipzig, 1839, Bd. xvi. S. 152. 



4 " Ziir Kenntniss der Verbreitungdes Hfematins," Sitzungsb. d, k. Akad. d. IVissensch. , 

 Wien, 1861, Bd. xliv. S. 615-630. 



5 " Observations with the Spectroscope," Journ. Anat. and Physiol., London, 1867, 

 S. 114. 



6 "Optische Eigenschaften des Blutfarbstoffs, " Centralbl. /. d. mcd. Wissensch., Berlin, 

 1867, S. 196. 



7 "A Contribution to the Knowledge of Haemoglobin," Proc. Roy. Soc. 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. 



