from The Century Dictionary.
- noun A substance used to bring about the transfer of oxygen so as to produce a compound of this element which would not be formed in the absence of the carrier. Thus, nitrogen dioxid servos as a carrier of oxygen derived from the air to sulphur dioxid and water in the lead-chamber process for making sulphuric acid.
Sorry, no etymologies found.
Why mammals have a common blood structure (Types A,B,O also in chimps) based on cells, in contrast to circulating proteins (cf. hemocyanin, a copper-based porphyrin oxygen-carrier found in e.g. lobsters).
So at last the redness, of the oxygen-carrier is turned to account.