

THE CIRCULATING LIQUIDS OF THE BODY & 



When a solution of oxyhaemoglobin of moderate strength 

 is examined with the spectroscope, two well-marked absorp- 

 tion bands are seen, one a little to the right of Fraunhofer's 

 line D, and the other a little to the left of E. A third band 

 exists in the extreme violet between G and H. It cannot 

 be detected with an ordinary spectroscope, but has been 

 studied by the aid of a fluorescent eye-piece (Soret), by 

 projecting the spectrum on a fluorescent screen, and by 

 photographing the spectrum (Gamgee). The addition of a 

 reducing agent, such as ammonium sul- 

 phide, causes the bands in the visible 

 spectrum to disappear, and they are 

 replaced by a less sharply-defined band, 

 of which the centre is about equidistant 

 from D and E. This is the charac- 

 teristic band of reduced haemoglobin. 

 The spectrum of ordinary venous blood 

 shows the bands of oxyhsemoglobin. 



Carbonic oxide haemoglobin is a representa- 

 tive of a class of haemoglobin compounds p IG 9 CRYSTALS OF 

 analogous to oxyhasmoglobin, in which the OXY-H^EMOGLOBIN. 

 loosely-combined oxygen has been replaced a, human ; d, squirrel ; 

 by other gases (carbon monoxide, nitric c > guinea-pig, 



oxide) in firmer union. Its spectrum shows 



two bands very liice those of oxyhaemoglobin, but a little nearer the 

 violet end. Carbonic oxide haemoglobin is formed in poisoning 

 with coal gas. Owing to the great stability of the compound, the 

 haemoglobin can no longer be oxidized in the lungs, and death may 

 take place from asphyxia. It is, however, gradually broken up, and 

 this is an indication that artificial respiration may sometimes be of 

 use in such cases. 



Methaemoglobin is a derivative of oxyhaemoglobin which can be 

 formed from it in various ways, e.g., by the addition of ferricyanide 

 of potassium or nitrite of amyl (Gamgee), or by electrolysis (in the 

 neighbourhood of the anode). It very often appears in an oxyhaemo- 

 globin solution which is exposed to the air. It has been found in 

 the urine in cases of haemoglobinuria, in the fluid of ovarian cysts, 

 and in haematoceles. The strongest band in its spectrum is in the 

 red, between C and D, but nearer C, nearly in the same position as 

 the band of acid-haematin. Reducing agents, such as ammonium 

 sulphide, change methaemoglobin first into oxyhaemoglobin and then 

 into reduced haemoglobin. It has by some been regarded as a more 

 highly oxidized haemoglobin than oxyhaemoglobin. Rebutting 

 evidence has, however, been offered to the effect that the same 



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