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 (Haldahe) (p. 248). 

 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 



if* 



\l'/''-~. 



Carbonic ox-ideftb. 

 Hafmcch romotfen 

 Hae-matcfiorfihyrm (acidj\ 



ft ctd Haematin I ^ fc 



Alkaline Haematm r, hle f. 

 Reduced hb, \ band 



rig 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- 



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

 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, h cemochromogen is first 

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



porphyrin. If oxy- 



Live 29-3 



TTueclts 29'2 



s,heirTv lungs Zi'7 

 Bones 8'Z 



genital organs 6'3 

 ^Ain 27 



Kidneys 1'6 



Nerve centres 7'2 

 SpJeen "i- 



Fig. 16. Diagram to illustrate the Distribution of the 

 Blood in the Various Organs of a Rabbit (after Ranke's 

 Measurements). The numbers are percentages of the 

 total blood. 



gen be present, hae- 

 matin is the final 

 product. Haematin 

 may be considered 

 as the compound 

 which haemochro- 

 mogen forms with 

 oxygen. By the 

 action of alkalies re- 

 duced haemoglobin 

 yields haemochro- 



mogen, which is stable in alkaline solution, and gives a beautiful 

 spectrum with two bands, bearing some resemblance to those of oxy- 

 hsemoglobin, but placed nearer the violet end. The band next the red 

 end is much sharper than the other (p. 76). Haemochromogen binds 

 exactly the same amount of oxygen as the haemoglobin from which it is 

 derived, and it is due to the haemochromogen in its molecule that the 

 blood-pigment fulfils its function of taking up and transporting oxygen. 

 Hesmatin (C 32 H 320^4. 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 oxgyen 

 (Practical Exercises, p. 75). 



H (ematoporphyrin (C 33 H 38 O 6 N 4 ), or iron-free haematin, may be ob- 

 tained from blood or haemoglobin by the action of strong sulphuric 

 acid, from haematin or haemin by the action of hydrobromic acid. It 



