04 THE BLOOD AND THE LYMPH 



oxygen in the inspired air, as in life at high altitudes, or a difficulty in 

 its absorption through the lungs, as in congenital heart disease. 



The red cells produced following hemorrhage and in simple anemia 

 contain less than the normal amount of hemoglobin, but their shape and 

 size are approximately normal, and few nucleated cells are present. In 

 the regeneration of red cells -which is found in pernicious anemia, we 

 find the cells containing an unusually large amount of hemoglobin. 

 The red cells in this disease have abnormal forms, many being large, 

 with or without a nucleus, and containing, basic staining granules. 

 This type of blood cell formation is due to degenerative changes. 



The Fate of the Erythrocytes 



The length of life of the red blood cell is unknown. Estimates based 

 ii] ton the daily excretion of bile pigments are not reliable, since Hooper 

 and Whipple have shown that the pigments, in part at least, arise from 

 pigments which the liver has made' in excess of its needs for the manu- 

 facture of hemoglobin, and which, not being needed, are excreted."' 

 There is no question hoAvever that every erythrocyte sooner or later 

 undergoes disintegration, a process formerly thought to be ushered in 

 by the ingestion of the red blood cell by a phagocyte in the spleen or 

 in a hemolymph gland, the hemoglobin of the disintegrated cell being set 

 free and carried to the liver, where it is broken up into hematin, which 

 the body stores for future use, and into bile pigments, which are ex- 

 creted. Rous and Robertson 6 fail to find evidence that this process 

 occurs in man to an extent sufficient to account for the normal destruc- 

 tion of the blood cells. However they have recently found another and 

 unsuspected method for blood destruction in all animals thus far 

 studied — namely, the disintegration of the blood cells by fragmentation 

 while they are circulating, without loss of their hemoglobin. These 

 fragmented cells are found most frequently in the spleen. They believe 

 that the small ill-formed cells, known as microcytes and poikilocytes, 

 observed in severe experimental anemias, are due not to the fact that 

 they are produced by the bone marrow, but rather to the fact that the 

 marrow in its anemic condition is not able to produce a resistant ery- 

 throcyte, and fragmentation therefore takes place too readily. A sim- 

 ilar condition may exist in the severe anemias of man and account for 

 the general high resistance of the red cells found in the blood of these 

 patients, inasmuch as the weak cells are generally fragmented very soon 

 after they are formed. Long ago Ehrlich stated that the microcytes 

 and poikilocytes of anemia are the result of fragmentation of the cells 

 in the circulating blood, but he believed that this fragmentation was a 



