472 
C. A. MAO MUNN. 
In 1878 Fredericq, 1 in a paper on the physiology of Octopus 
vulgaris, showed that the blue colouring matter of the blood of 
this species is combined with a proteid and with copper ; the 
proteid is more complex than an ordinary proteid, since it yields 
one as a decomposition product. Fredericq found that this blood 
lost its colour in vacuo and regained it on treatment with 
oxygen ; and he observed its blue colour in the arteries of the 
living Octopus. He found that it showed no absorption bands. 
The following year Fredericq 2 stated that the colouring matter 
of the blood of the lobster is identical with that of Octopus; 
it behaves in the same manner in vacuo and on treatment with 
oxygen; he further showed that the statements of Jolyet and 
Regnard with regard to Crabs’ blood also apply to the blood 
of the lobster, which is blue with reflected and brownish with 
transmitted light. The red pigment also present does not 
belong to the albuminous constituents; it contains no copper, 
and has nothing to do with the change of colour of the blood, 
nor is it constantly present in the blood. The same authority 
showed that the blood of Helix and Arion contains a similar 
blue colouring matter to that of Octopus, Homarus, and Crabs, 
i. e. haemocyanin. Prof. Lankester 3 has shown that the blood 
of Limulus and Scorpio becomes blue on exposure to air, 
and contains hsemocyanin ; and Golch and Laws, 4 of Oxford, 
have found that in Limulus polyphemus the blood colour- 
ing matter was allied to haemocyanin, and contained a proteid 
united to copper, like it. 
Krukenberg 5 has examined the blood ofEledonemoschata, 
S epi a officinalis, Homarus vulgaris, Carcinusmaenas, 
Eriphia spinifrons, Portunus depurator, Grapsus 
1 * Extr. des Bulletins de l’Acad. r. de Belgique,’ 2 ser., t. xlvi, No. 11, 
1878, pp. 4—21. 
2 ‘Extr. des Bulletins de l’Acad. r. de Belgique,’ 2 ser., t. xlvii, No. 4, 
Avril, 1879. 
3 ‘Quart. Journ. Micro. Sci.,’ 1878, p. 453, et seq. ; ibid., vol. xxiv, p. 151. 
4 ‘ Brit. Assoc. Reports,’ 1884. 
5 ‘ Vergleich. physiol. Studien.,’ 1st Reihe, 3 Abtli., 1880, S. 72, &c. The 
above account of the literature of hsemocyanin is partly taken from this work. 
I am also indebted to Gamgee’s ‘ Physiological Chemistry ’ for a few references. 
