174 PHYSIOLOGY. 



Both the haemoglobin-content and the corpuscles augment to 

 the same degree in high altitudes. A return of the individual to a 

 lower level is followed, in twelve to thirty-six hours, by a distinct 

 fall both in haemoglobin and the number of corpuscles. 



In pernicious anaemia the marrow fat of the bones is invaded 

 by the red marrow which normally exists at the extremities of bones, 

 the whole marrow becomes red arid a manufactory of red corpuscles. 

 Iron and arsenic seem to stimulate the bone-marrow to produce red 

 corpuscles. The final fate of red blood-corpuscles is to be broken 

 up chiefly in the liver and excreted in the bile as bile pigment. If 

 the disintegration of red corpuscles is very great the pigment may 

 obstruct the bile capillaries and the bile be reabsorbed, producing 

 "haematogenous jaundice." 



There is both an increased destruction and an increased regen- 

 eration of red corpuscles in pernicious anaemia. The blood-count 

 may be reduced to 143,000 per cubic millimeter. 



In chlorosis the corpuscular-count falls considerably. A de- 

 crease to half a million per cubic millimeter is the lowest limit 

 compatible with life. 



Life-cycle of the Red Corpuscles. The life of the red corpuscle 

 is unknown. In experimental transfusion the red corpuscles disap- 

 pear at the end of a variable period. The destruction of blood- 

 corpuscles in extravasations does not give us any precise results. 

 Observing the differences in color, consistency, and chemical reac- 

 tion, it is found that they correspond to the different degrees of 

 development. This shows that in the blood there is a constant 

 destruction and renewal of the corpuscles. 



Quincke believes that a red corpuscle lives from three weeks to 

 a month. 



Besides the liver, the spleen is also a place for the destruction 

 of the red corpuscles. 



Counting Red Corpuscles. Various methods have been devised 

 for counting the number of corpuscles, the instruments used receiv- 

 ing the name Jicemacytometers. Modifications are numerous, but 

 underlying all of them is one main principle, namely: the actual 

 counting of the corpuscles within a certain measured bulk. To 

 preserve the shape and integrity of these little bodies during the 

 technique it is necessary to dilute the sample of blood with some 

 solution whose specific gravity exactly equals that of the blood- 

 serum. Some of this blood-solution is then placed upon a gradu- 

 ated slide beneath a microscope for counting, when the number 

 per cubic millimeter is easily computed. 



