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Studies in the Regeneration of Blood. 191 



The figures in the braces represent determinations on the same 

 patient on different dates. 



95 (i677) 

 Studies in the regeneration of blood. 



By E. M. K. GELLING and H. H. GREEN. 



[From the Sheffield Laboratory of Physiological Chemistry in Yale 

 University, New Haven, Conn.] 



In continuation of the unpublished studies of Jencks in this 

 laboratory upon blood regeneration in the rat, it is desired to 

 report the following data: The normal erythrocyte count of 

 rat's blood ranges between 7.5 and 10.5 millions per cubic milli- 

 meter; and the hemoglobin content between no and 140, as 

 determined by the Smith-Cohen method. Data from rats of 

 varying ages and different sex appear to fall within these limits. 



Single hemorrhages, equivalent to 2 per cent, of the body 

 weight, and double hemorrhages, of 2 per cent, on two successive 

 davs, were carried out. With the latter procedure it was found 

 possible to reduce the erythrocyte count and hemoglobin content 

 to about one third normal. 



On the usual mixed food regeneration of blood was complete 

 in from .7 to 10 days after single hemorrhage, and in 10 to 14 days 

 after double hemorrhage; erythrocyte count and hemoglobin 

 content being taken as indices of regeneration. During starva- 

 tion regeneration followed single hemorrhage in normal time, but 

 was accompanied by heavy loss in body weight. In starvation 

 following double hemorrhage, the animals usually succumbed 

 before regeneration was complete. Splenectomized rats appear 

 to regenerate in normal time on the normal diet. Rats reared 

 upon the Osborne-Mendel fat-deficient diet showed normal 

 erythrocyte count and hemoglobin content, and after double 

 hemorrhage regenerated in normal time upon the same diet. 

 On a diet deficient in either protein, vitamine, or mineral matter, 

 blood regeneration was appreciably delayed, after double hemor- 

 rhage. Hence the data at present available suggest that although 

 blood is parasitic upon the other tissues, any one of the three 



