54 



THE CIRCULATING LIQUIDS OF THE BODY 



globin, unlike oxy haemoglobin, parts with no oxygen to the vacuum, 

 while, on the other hand, in the presence of reducing agents it yields up 

 its oxygen even more readily than oxyhaemoglobin does (Haldane) 

 (p. 249). 



By the action of acids or alkalies oxyhaemoglobin is split into a pig- 

 ment, haematin, and a protein, globin, belonging to the histon group. 

 It is easily precipitated from solution by ammonia. On hydrolysis, it 

 yields a large amount of histidin.to which its basic properties are chiefly 



rS* 



& 



|r|**** 



J_LL 



Carbonic ox, idem I *?//# 



tfctftnoch t~o mo qe * (bands 

 Haematojiorfih i/rin facid)\ 

 * 



ftcid Haematin 

 Alkaline Haematin 

 Reduced Hb. 



Vfi. 



Fig. 15. Diagram to show the Chief Characteristics by which Haemoglobin and 

 some of its Derivatives may be recognized Spectroscopically. The position of 

 the middle of each band is indicated roughly by a vertical line. 



due. From 100 grammes of oxyhaemoglobin about 4 grammes of hae- 

 matin are obtained. As to the pigment moiety, when haemoglobin is 

 acted on by acids in the absence of oxygen, hcemochromogen is first 

 formed, which then gradually loses its iron and is changed into haemato- 

 porphyrin. If oxygen be present, haematin is the final product. 

 Hsematin may be considered as the compound which haemochromogen 

 forms with oxygen. By the action of alkalies reduced haemoglobin 

 yields haemochromogen, which is stable in alkaline solution, and gives 



a beautiful spectrum 

 with two bands, 

 bearing some resem- 

 blance to those of 

 oxyhaemoglobin, but 

 placed nearer the 

 violet end. The band 

 next the red end is 



CreaT ;.-t39ls, heart* *vngs Zi'7 

 7k>nes 8'Z 



<renrfe] organs 6-3 



Kidneys 1'6 



Nerve centres J'2 

 Spleen 1 



Fig. 16. Diagram to illustrate the Distribution of the much sharper than 

 Blood in the Various Organs of a Rabbit (after Ranke's the other (p. 76). 

 Measurements). The numbers are percentages of the Haemochromogen 

 total blood. binds exactly the 



same amount of oxy- 

 gen as the haemoglobin from which it is derived, and it is due to the 

 haemochromogen in its molecule that the bood - pigment fulfils its 

 function of taking up and transporting oxygen. 



Hasmatin (C 32 H 32 O 4 N 4 .FeOH), the most frequent result of the 

 splitting up of haemoglobin, is generally obtained as an amorphous 

 substance with a bluish-black colour and a metallic lustre, insoluble 

 in water, but soluble in dilute alkalies and acids, or in alcohol containing 

 them. In addition to the iron of the haemoglobin, haematin contains 

 the four chief elements of proteins carbon, hydrogen, nitrogen, and 

 oxygen (Practical Exercises, p. 75). 



