x CO-HAEMOGLOBIN 497 



The fact that ' acid-haematin,' or as Cohnheim puts it, 'acid- 

 haemoglobin,' is also formed by the prolonged action of C0 2 is of 

 especial biological interest in connection with Bohr's recent work on 

 the dissociation of oxyhaemoglobin by C0 9 , as explained on p. 490. 



KathcemogloUn 



Kathcemoglobin is a compound which v. Klaveren 1 believes to 

 have prepared by the action of alkalies on haemoglobin. It is inter- 

 mediate between haemoglobin and haematin, judged by its spectrum, 

 and is probably a mixture of alkaline haematin and oxy haemoglobin. 

 (The author.) 



Carbonic Oxide Haemoglobin 



Lothar Meyer in 1858 was the first to observe that oxygen is 

 replaced in haemoglobin by an equal volume of CO. The first full 

 account is given by Hoppe-Seyler 2 in 1864. CO-hsemoglobin differs 

 from oxyhaemoglobin in possessing a pinkish colour; the foam 

 is violet. The crystals are isomorphic with those of oxyhsemoglobin, 

 but are darker and of a more bluish tint. According to Ewald, 3 their 

 pleochroism is not strong but very pretty, as with altered nicols 

 the colour changes from a purple red to nearly white. Its absorption- 

 bands are very similar to those of oxyhaemoglobin, but displaced 

 somewhat nearer to D ; the second band is also less intense ; mea- 

 sured at the same place as oxyhaemoglobin, the quotient of the 

 absorption-coefficient is T13, according to Hiifner and Kiilz. 4 No 

 differences were observed between solutions of CO-haemoglobin and 

 fresh blood containing CO ; neither was there any difference between 

 the blood of different animals. According to Gamgee, a band lies in 

 the violet between h and G ; it is narrower than is the corresponding 

 oxyhaemoglobin band and placed more towards the red end. Its 

 centre lies at A420'5. 



Bock 5 showed that the dissociation-curve of CO-haemoglobin rises 

 very sharply up to a tension of about 0'5 mm., and afterwards very 

 slowly. Hiifner finds, with a tension of 0*5 mm. carbonic oxide, that 

 a haemoglobin-solution becomes saturated to 87 per cent at 31. 

 Haldane and Lorrain Smith 6 found that at 15 and a tension of 



1 K. H. L. v. Klaveren, Zeitschr. f. physiol. Chem. 33. 293 (1901). 



2 F. Hoppe-Seyler, Zentralbl. f. d. med. Wissensch. 1864, p. 52 ; Med.-chem. Unter- 

 suchungen, p. 169 (1867). 



3 A. Ewald, Zeitschr. f. Biolog. 22. 459 (1886). 



4 R. Kulz, Zeitschr. f. physiol. Chem. 7. 384 (1883). 



5 Job. Bock, Zentralbl. f. Physiol. 8. 385 (1894). 



6 J. Haldane and J. Lorrain Smith, Journ. of Physiol. 22. 253 (1897-98). 



2 K 



