VI. Further experiments upon the blood volume of mammals and its relation to the surface area of the body

Abstract

In previous papers* we have shown that the blood volume of normal and healthy mammals, such as rabbits, guinea-pigs, and mice, is satisfactorily expressed by the formula B = W n / k , where B is the blood volume in cubic centimetres, W the weight of the individual in grammes, n approximately ⅔, and k a constant (calculated from the experiments), which varies with the particular species of animal. This formula indicates that the smaller and lighter animals of any given species, which have a relatively greater body surface than the heavier ones, have also a relatively greater blood volume—in other words, the blood volume can be expressed as a function of the body surface , and it must therefore be misleading to express it in per cent, of the body weight, since when so expressed it is not a constant for any given species of mammal. As it was of interest to ascertain whether wild animals of closely allied species would differ greatly as regards their blood volume from the above-mentioned tame animals, we have determined the blood volume of hares, wild rabbits, and wild rats.

The size of the trachea in warm-blooded animals, and its relationship to the weight, the surface area, the blood volume, and the size of the aorta

“…The ratio between these figures (3-27 and 17*34) is also almost exactly the same as that which was found between the corresponding figures in the case of the blood volume (2), although in that case the mean deviations themselves were much smaller (namely, 1*39 and 7'82 per cent, respectively), owing to the much greater intrinsic accuracy of the technique.…”

“…But wherever observations covering a wide range of weight are concerned it is essential to make use of the " best n '' in order to obtain reliable results. In this connection it may be noted incidentally as a point of interest that the ratio between the deviations just quoted for n = -f and n = best n ,namely, 3*81 /2* practically identical with the corresponding ratio already given elsewhere (2) in the case of the blood volume, namely, 2,0 8 /l'39 (i.e. 1*5).…”

“…In view of the fact that the carriage of oxygen is one of the chief functions of the circulation, and that the volume of the blood (1), (2), and the aortic area (3), (4), (area of cross-section of aorta), have been shown by us to be proportional to the body surface in warm-blooded animals, while, as we have also found, the total oxygen capacity is the main factor in deter mining the size of the heart (5), it appeared to be of interest to examine the size of the channel by which the oxygen gains access to the lungs. Accordingly, the trachea was measured in two species of mammal and one bird, namely, guinea-pig, rabbit, and ptarmigan.…”

Translating dosages from animal models to human clinical trials—revisiting body surface area scaling

“…The second, a work by Pinkel in 1958 (17), suggests a seemingly closer relationship for a reported therapeutic dose of 5 chemotherapeutic drugs between humans and 1‐3 of 4 selected species (rat, mouse, hamster, and 10 kg dog) when BSA scaling was used rather than by body weight scaling (17). Pinkel supports the claim that blood volume was scalable between species by BSA using works published by Dreyer and Ray in 1910 and in 1912 (18, 19), which were limited to comparisons among mice, guinea pigs, and rabbits (11, 17). Pinkel also cites work relating blood volume, plasma proteins, and glomerular filtration rate scaling by BSA between humans of various sizes, rather than between species.…”

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“…Giving such high doses chronically may however have dire consequences. Small animals excrete compounds more rapidly than larger animals in a rather systematic manner, therefore studies conducted in animals would need dose adjustments when they are applied to humans 42,43 . A non-toxic dose in rats can be toxic to humans if safety factor is not accounted for.…”