CHAPTER XI 



THE CORPUSCLES OF THE BLOOD 



The Red Blood-Corpuscles. The red blood-corpuscles, or erythro- 

 cytes, are the elements to which is due the red colour of the blood of 

 all the vertebrate animals except Amphioxus, which has colourless 

 blood. They were first seen in human blood by Leuweiihoek in 1673. 

 They had been previously seen in frog's blood by Swammerdam in 

 1658. 



Human red blood-corpuscles are non-nucleated biconcave discs 

 having a diameter of about 7 to 8 ,u>. Two views are held as to their 

 structure. According to one view they are to be regarded as capsules 

 containing the red pigment, haemoglobin (Hb) probably in a special 

 colloidal state. The amount of the pigment is so great that it could 

 not be in solution. A red corpuscle contains 32-05 per cent. Hb, and 

 only 63-21 per cent, water, and so strong a solution of Hb cannot be 

 made. The other view regards them as consisting of a stroma or 

 network in which the pigment is enmeshed. In either case the outer 

 surrounding structure is protein in nature, richly impregnated with 

 lecithin and cholesterin. It has been suggested, but not proven, that 

 these lipoid bodies stand guard over the corpuscles, and determine 

 what substances may pass into the corpuscles and what may not. 



The form of the red corpuscle varies in different species. Man 

 and the other mammalia, with the exception of the camelidse (camel, 

 llama, etc.), have non-nucleated biconcave discs. Camels have long 

 non-nucleated elliptical corpuscles. Birds, reptiles, fish, have elliptical 

 nucleated corpuscles. The number to each cubic millimetre varies 

 in general with the size the larger the corpuscle, the smaller the 

 number per cubic millimetre. The following table shows the size 

 and number per cubic centimetre in various animals : 



The corpuscles are endowed with elasticity, and alter their shape 

 in passing through the capillaries. The red corpuscles represent 



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