824 



GEOEGE R. MINOT AND AKLIE V. BOCK 



TABLE I 



transfusion is decided upon in cases of chronic anemia the procedure 

 should not be postponed for weeks to see first if the patient will not regen- 

 erate some of his own blood. After this case had received 600 c.c. of blood 

 the increase in hemoglobin was equal to 50 per cent of the amount in the 

 circulation before transfusion. Even so, the total hemoglobin remains 

 only one-third of the normal. Though this amount of hemoglobin is in- 

 sufficient to enable the organs of the Body to function well, it permits them 

 to act distinctly better than with the amount of hemoglobin present before 

 transfusion. In fact, it is rather striking that a slight elevation of the 

 hemoglobin level will often largely remove the symptoms of anemia. 



The actual increase per c.c. of blood in the number of red corpuscles 

 after transfusion depends upon such factors as the amount of blood trans- 

 fused, the amount of plasma in the recipient's circulation, the degree of 

 anemia present and certain unknown factors among which may be a 

 possible redistribution of blood, as Huck has suggested. When about 

 600 c.c. of blood is given, the usual increase in the number of corpuscles 

 is from 200,000 to 700,000 per c.mm., and the hemoglobin is increased 

 within a range of 5 to 20 per cent. There may not be a very close rela- 

 tionship between the increase in the number of corpuscles and the per- 

 centage increase in hemoglobin. Rarely, after transfusion, no increase in 

 red corpuscles can be demonstrated by counts. 



The beneficial effect of the transfused red cells in increasing the oxygen 

 carrying capacity of the blood must be regarded as only temporary. This 

 is because they do not remain indefinitely in the circulation of the re- 

 cipient. According to the work of Ashby the life of transfused corpuscles 

 may be as long as thirty days and under certain conditions even much 

 longer. Previous work has suggested that 10 per cent of the red 

 corpuscles are destroyed daily. Though the transfused red cells them- 

 selves increase temporarily the oxygen carrying capacity, transfusion will 

 often tide the patient over a period of time until he can furnish enough 

 cells to serve satisfactorily the functions of the body. 



In considering the necessity for transfusion, emphasis usually is to be 

 placed upon the hemoglobin content of the blood. Fluid substitutes for 



