Studies in the regeneration of blood

Abstract

In continuation of the unpublished studies of Jencks in this laboratory upon blood regeneration in the rat, it is desired to report the following data: The normal erythrocyte count of rat's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 millimeter; and the hemoglobin content between 110 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 days, 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 starvation 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 hemorrhage. Hence the data at present available suggest that although blood is parasitic upon the other tissues, any one of the three dietary factors just mentioned can be made a limiting factor in the rate of regeneration, if the hemorrhage is sufficiently severe.