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dealt with the following subjects : — 1st. Distribution of Haemo- 
globin in the Animal Kingdom ; 2nd. Some derivatives of 
Haemoglobin ; 3rd. The Action of Cyanogen Gas on Haemo- 
globin ; 4th. Chlorocruorin(the green blood constituent of some 
Annelids) ; 5th. Chondriochlor, or Sponge-chlorophyl ; the 
Green Chlorophyl-like body found in the cortical substance 
of Spongilla. It was shown that cyanogen gas-like carbonic 
oxide and nitric oxide changes the colour and spectrum of a 
solution of blood-clot, and renders the solution insensible to 
the action of reducing agents. After keeping for some hours 
the solution, which has been shaken with cyanogen gas, 
becomes orange-brown, due to the formation of hydrocyanic 
acid, and subsequently of the cyanhaematin of Hoppe Seyler. 
Chlorocruorin, which has a spectrum very different from that 
of Haemoglobin or Erythrocruorin, was shown to yield a 
spectrum by treatment with cyanide of potassium and sul- 
phide of ammonium, identical with that to be obtained in 
the same way from Haemoglobin. Thus the relationship of 
the two bodies is established. 
Spectroscopy. — The Spectrum of Diatomin. By PI. 
Smith. Silliman’s Journal, July, 1869. — Mr. Smith has 
made use of one of the Sorby-Browning micro-spectroscopes, 
and has examined the endochrome of the diatom therewith. 
He says he can “ unhesitatingly assert that the spectrum of 
diatomin is identical with that of chlorophyl.” By his own 
account of the matter he is wrong in so doing, for he has 
only obtained from diatomin a dark band in the extreme red, 
which is identical with one presented by chlorophyl under 
certain conditions. What is ordinarily called chlorophyl 
gives, however, more than this one band, and it is not right 
to speak of spectra as “ identical ” where only one band is 
found to agree in the two. The fact is, so little is yet really 
known of chlorophyl spectra, that the term chloi'ophyl can 
only be used generieally at present. No doubt diatomin 
belongs to this genus, but the species have yet to be fairly 
discriminated. 
