208 PROPORTION OP RED CORPUSCLES. 



the Red Corpuscles draw into themselves nearly the whole 

 of the iron, phosphorus, and potass, which the chyle pours 

 into the circulating current ; and that they modify a large pro- 

 portion of the solid matter of the blood, that which they con- 

 tain being notably different in composition from that of the 

 liquor sanguinis, which does not differ, save in the proportion 

 of its components, from the liquid portion of Chyle or Lymph. 



233. The proportion of Red Corpuscles to the whole mass 

 of the blood varies greatly in different animals, and even in 

 different states of the same animal. It is greatest in those 

 which have the highest muscular vigour and activity, and 

 which consume the largest quantity of oxygen by respiration ; 

 hence these particles are rather more numerous in the blood 

 of Birds than in that of Mammals, and far more abundant 

 in these last than in Reptiles or Fishes. Again, they are 

 more numerous in Men of ruddy complexion, strong pulse, 

 and active habits, than in those of pale skins, languid circu- 

 lation, and comparatively feeble powers. In a healthy Man 

 they seem to constitute ajbout half the mass of the circulating 

 blood ; but they contain as much as three-fourths of its solid 

 matter, the proportion of dry corpuscles being about 150 in 

 1000 parts of blood, whilst that of the other solid matters 

 is about 50. A very marked decrease occasionally presents 

 itself in disease ; the proportion of dry corpuscles being some- 

 times reduced as low as 27. When too abundant, they pro- 

 duce what is known as the plethoric condition of the body, 

 in which haemorrhage from the bursting of a blood-vessel is 

 liable to occur. Their number is effectually reduced by bleed- 

 ing ; and the aspect of those who have suffered from extreme 

 loss of blood, gives sufficient evidence that the deficiency is 

 not made-up for a long period. The most effectual means of 

 restoration, in cases where the proportion of blood-corpuscles 

 is too low, is a highly nutritious diet, with the administration 

 of iron as a medicine ; for this substance seems to have the 

 power of hastening the reproduction of the corpuscles, being 

 itself an essential ingredient in their contents ; and there 

 are facts which show its remarkable power of increasing their 

 amount in proportion to the mass of the blood. 



234. It appears that the red corpuscles, like other cells, 

 have a certain allotted term of life ; and as they are con- 

 tinually dying, they must be as continually reproduced. The 



