228 THE BLOOD 



Quincke 1 attempted to estimate the blood volume from the change in the blood 

 counts before and after transfusion. Lindemann 2 calculates the volume of the 

 blood during transfusion with the help of the following factors: c, the cell per- 

 centage by volume of the blood introduced ; 6, the quantity of blood introduced, 

 both being open to direct measurement ; I, the cell percentage by volume of the 

 patient's blood after the transfusion; x, the initial volume and a, the cell content 

 of the initial volume. Then: 



xa + be = l(x + 6) 

 xa + be = Ix + Ib 

 xa Ix = Ib be 

 x(a I) = Ib be 

 _ Ib - be 

 ~~ a-l 



Thus: If the amount of blood transfused is 1500 c.c., the amount of blood previously 

 withdrawn for tests 70 c.c., the cell volume before transfusion 13.7 per cent., the 

 cell volume after transfusion 25.5 per cent, and the cell volume of the donor 40 

 per cent., then the blood volume of the patient amounts to: 



40 X 1500 - 25.5 X 1500 



jr^-= rir-= = 1843 c.c. + 7.0 c.c. =1913 c.c. 



zo.o lo.7 



The circulating blood of the dog is estimated at about 7.7 per cent, 

 of the body weight, in the cat and rabbit at 5 per cent, and in birds at 

 10 per cent. Similar values have been found by Bischoff 3 and Weber 

 and Lehmann 4 in guillotined criminals. Based upon these early figures, 

 the amount of blood present in an animal has always been calculated at 

 one-thirteenth of the body weight. The experiments of Haldane and 

 Smith, however, seem to prove that this figure is too high. Having 

 obtained an average value of 0.49 per cent., these authors believe that 

 the total quantity of blood in man equals only one-twentieth of the 

 body weight. Thus, a man weighing 70 kg. possesses about 3684 

 grams of blood. 



While the assumption that the quantity of blood preserves a direct 

 relationship to the weight of the body, is a natural one to make, it 

 should be remembered that we are not dealing with perfectly constant 

 conditions, because the weight is subject to frequent changes. A de- 

 position of fat, a greater development of the musculature, a transfer of 

 lymph and other temporary and permanent alterations are prone to 

 interfere with the establishment of such a relationship. 



The Distribution of the Blood. The blood having been ejected 

 from the heart, is distributed to the different tissues and organs of the 

 body in amounts commensurate with their activities. In general, it 

 may be said that the tissues which form the framework of the body 

 need a relatively small quantity, because, when fully grown, their 

 upkeep and additional slight growth do not necessitate intense 

 metabolic changes. Glandular tissues, on the other hand, need a 



1 Deutsch. Archiv fur klin. Med., xx, 1877, 27. 



2 Jour. Am. Med. Assoc., Ixx, 1918, 1210. Mention should also be made of 

 the antitoxin method of von Behring (Munchener med. Wochenschr., Iviii, 1911, 

 655). 



3 Zeitschr. fur Zoologie, vii, 1855 and ix, 1857. 



4 Zeitschr. fur physiolog. Chemie., Leipzig, 1853. 



