x HAEMOGLOBIN '473 



substance may either render the albumin unattackable, as do formic 

 or acet-aldehyde when they alter albumin in such a way that it is no 

 longer acted upon by trypsin, while it is still digested by pepsin, or 

 the third substance may alter the ferment, e.g. OH-ions acting on pepsin, 

 in which case the addition of fresh unaltered ferment will result in 

 normal digestion. The author also believes that the resistance offered 

 by haemoglobin to putrefaction and to tryptic digestion depends on 

 the same cause. 



Haemoglobin differs from globin and all simple albumins in being 

 dextro-rotatory according to Gamgee and Croft Hill, 1 who found 



Haemoglobin . . . . a c = + 10'4 

 Globin . . . . a c = -54-2 



Gamgee 2 has further observed that haemoglobin and its various com- 

 pounds with gases are diamagnetic in an electrical field, while haematin 

 is strongly magnetic. 



Histohsematins have been carefully investigated by MacMunn. 3 

 They are allied to the haemochromogens and subserve a respiratory 

 function, as " their bands are intensified by alkalies and enfeebled by 

 acids, intensified by reducing agents and enfeebled by oxidising 

 agents. " MacMunn has described the following bands : * 



Stomach wall of cat (blood-free) 



a A613-A593 

 P A569-A563 

 7 A556-A551 

 Kidney of cat 



a A613-A596-5 

 P A569-A563 

 7 A556-A550 



That special histohaematin found in muscle MacMunn has called 

 ' myohaematin.' Its absorption spectrum " is practically the same 

 throughout the whole animal kingdom." It is best studied in the 

 papillary muscles of the heart. 

 Heart of hare 



a A613-A600 

 P A569-A563 

 7 A556-A550 



1 A. Gamgee and Croft Hill, Ber. d. deutsch. chem. Ges. 36. I. 913 (1903). 



2 A. Gamgee, Proc. Roy. Soc. 68. 503 (1901). 



3 MacMunn, Phil. Trans., London, 177. 235 (1886). 



4 Quoted from M'Kendrick's textbook of Physiology, 1. 138 (1888) ; see also 

 Journ. of Physiol. Q. 51 (1887). 



