RESPIRATION 77 



species. The following table from Dhere's data shows how 

 close the correspondence is : 



Oxygen c.c. Copper mg. 



Animal. Temperature, per loo c.c. blood, per loo c.c. blood. 



From the recent work of Fox (1924) it would appear that 

 the green pigment, chlorocruorin, of certain polychaetes is 

 like haemoglobin and haemocyanin a substance which may 

 facilitate the carriage of oxygen to the tissues or its temporary 

 storage in the body. Chlorocruorin occurs in the Chlorhae- 

 midae and the Sabelliformia. The blood of these worms is 

 green by transmitted and red by reflected light. It was first 

 observed by Milne Edwards (1838) ; and its spectrum was 

 later studied by Ray Lankester (i 867-1 870). Oxy-chloro- 

 cruorin has two absorption bands, the limits of which were 

 given as 618-593/x/Lt and 576-5 54/>t/x. By reduction with 

 ammonium sulphide a derivative was obtained which had 

 only one band situated between 625 and 596/x/x. As this 

 reduced form reassumed the oxy-chlorocruorin spectrum on 

 shaking with air, Lankester concluded that it was respiratory 

 in function. 



The fact that chlorocruorin is reduced by reducing agents 

 and reoxidised in air is, however, insufficient reason for be- 

 lieving that reduction can take place in the body of the worm. 

 It has now been shown by Fox that oxy-chlorocruorin is reduced 

 in a vacuum, that is to say, it both takes up and gives up oxygen 

 according to the oxygen tension of the surroundings. Further- 

 more, its reduction by living tissues can be demonstrated by 

 spectroscopic observation of the blood of Spirographs in 

 contact with a piece of living muscle under a sealed cover- 

 slip. On removing the cover-slip the oxy-chlorocruorin 

 bands reappear. Assuming that the gas hberated by potas- 

 sium ferricyanide is oxygen, the oxygen capacity of the blood 

 of Spirographis was found by Fox to be about 6*17 per cent, 

 or 1 0*3 times the quantity dissolved in sea- water. This is 

 distinctly higher than the figure for the blood of Cephalopods 



