WILLIAM HARVEY AND HIS TIMES
the bird or animal would recover. Clearly, therefore, air was
essential for life and for combustion1.
Then Boyle's assistant, ROBERT HOOKE, to whose work as a
miscroscopist we shall presently refer (p. 190), proved that it was
the air, and not merely the movement, which sustained life. The
lungs were no longer to be regarded as bellows which cooled the
fiery heart. After removing the greater part of the chest wall in
a dog, Hooke made some openings in the surfaces of the lungs.
Then, by blowing into the windpipe, so that the air escaped
through the openings, he was able to keep the animal alive.
This was, in fact, the first demonstration of artificial respiration.
The interaction between the air and the blood was not yet
understood. This aspect of the problem of respiration was
solved by two Gornishmen, Lower and Mayow. RICHARD
LOWER (1631-91) tells us in his Tractatus de Corde (1669) that the
surface of a fresh blood clot becomes bright red when turned
round and exposed to air. Did this change in colour take place
also as blood circulated through the lungs ? 2 Lower repeated
the experiment of Hooke and found that it was indeed so. He
noted that when the artificial respiration was stopped, the blood
in the lungs became dark and venous, and that it became bright
red again when the respiration was resumed. Further, he took
some dark blood from the vena cava and <c perfused " it through
the lungs, noting that it then acquired the bright red hue of
arterial blood; The conclusion to be drawn from those experi-
ments was that the entrance of fresh air into the blood was essential
for the maintenance of life.8 " Were it not so, we could breathe
as well in the most filthy prison as in the most delightful pastures."
Lower was the first to perform blood transfusion from one animal
to another. This led to attempts to transfuse blood from an
animal into man as a means of resuscitation after haemorrhage.
As might be expected, the results were not encouraging, because
nothing was then known of haemolysis or of blood grouping.4
To Lower, also, medicine is indebted for the proof that the
1 W. Stirling, Some Apostles of Physiology, 19012, p. 39
* E. C. Hoff and P. M. Hoff, " The Life and Times of Richard Lower, 1631-91,**
Bull. Hist. Med., 1936, vol. iv. p. 517 ; K. J. Franklin, "Richard Lower and his
De Corde" Arm. Med. Hist., 1931,-vol. iii. p. 599
8 K. J. Franklin, " The Work of Richard Lower, 1631-91," Proc. Roy. Soc, Med.
(Sect. Hist.), 19312, vol. xxv. p, 113
4 M. W, Hollingsworth, " Blood Transfusion by Richard Lower in 1665," Am.
Med. Hist., 1928, vol. x. p. 213
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