THE BLOOD. 



173 



red corpuscles of man, when affected by malaria, are developed the 

 Plasmodium malarice. Their passage into the patient's blood-plasma 

 marks a paroxysm. 



Number of Red Corpuscles. The number of the corpuscles is 

 usually spoken of in terms of cubic millimeters; thus, in man there 

 are about 5,000,000 per cubic millimeter; in woman, about 4,500,000. 

 These figures represent the average number per. cubic millimeter, but 

 even in health and in the same individual there may be wide varia- 

 tions from this standard, to say nothing of the extreme diminution 

 experienced in certain pathological conditions. 



A B 



Fig. 49. Human and Amphibian Blood-corpuscles. (LANDOIS.) 



A, Human red blood-corpuscles: 1, on the flat; 2, on the edge; 3, rouleaux 

 of red corpuscles. B, Amphibian red corpuscle: 1, on the flat; 2, on edge. 

 C, Ideal transverse section of a human red corpuscle, magnified 5000 times. 

 o-&, linear diameter; c-d, thickness. 



As the corpuscles are small bodies floating in a liquid medium, 

 the student can easily understand why their number should be in 

 inverse ratio to the quantity of plasma, when the unit, cubic milli- 

 meter, is considered. Copious sweating and the loss of much water 

 by the bowels and kidneys occasion a temporary increase in their 

 number. Normally, there is no difference as to the number of 

 corpuscles in arteries and veins, provided there be no congestion in 

 the latter. 



A most interesting variation is that produced by habitation in 

 high altitudes. A two weeks' sojourn in a high mountain has been 

 known to show an increase from 5,000,000 to 7,000,000 per cubic 

 millimeter. This is accounted for by a real increase in the manu- 

 facture of corpuscles. 



