MECHANICAL HEART — GRIFFENHAGEN AND HUGHES 341 



tern. With the development of the microscope, Marcello Malpighi 

 (1628-1694) added the missing piece of the puzzle by the demonstra- 

 tion of the capillaries. 



It seems likely that once the importance of the heart was realized, 

 various thoughts must have been given to methods and means of re- 

 placing the heart by some artificial means. One such notion was 

 expressed as early as 1812 by Julien- Jean-Cesar La Gallois (1770- 

 1814), who observed: "If one could substitute for the heart a kind of 

 injection ... of arterial blood, either natural or artificially made 

 . . . one would succeed easily in maintaining alive indefinitely any 

 part of the body whatsoever (La Gallois, 1812). (See pi. 1.) It 

 remained, however, for other workers actually to undertake such 

 experiments. 



Techniques that were later employed in experiments leading up to 

 a mechanical substitution for the heart originated with the first at- 

 tempts at blood transfusion. To Richard Lower (1631-1691) of the 

 Royal Society of London goes the credit of performing the first direct 

 blood transfusion in February 1665. The results were published in 

 the first volume of the Philosophical Transactions for December 1666 

 (Maluf, 1954). 



Even though early experimenters in the field during the seventeenth 

 century recommended the use of volatile "staghorn salt" or "salmiak 

 spirit" as an anticoagulant, the inability to cope with the natural 

 phenomenon of blood clotting (among other factors) brought about 

 a decline of blood-transfusion experiments until the nineteenth 

 century. 



Two French physiological chemists, Jean Louis Prevost (1790- 

 1850) and Jean Baptiste Andre Dumas (1800-1884) , found that whip- 

 ping or twirling blood resulted in the deposition of fibrin on the churn- 

 ing instrument and prevented clotting in the defibrinated blood. Tliis 

 discovery led to a new series of experiments in blood transfusion, even 

 though the famous French physiologist Frangois Magendie (1783- 

 1855) presented experimental data to show that defibrinated blood was 

 toxic. An indecisive battle for and against the use of defibrinated 

 blood raged for several decades. 



In 1885, the saliva of the leech was found to contain a substance 

 named "hirudin," which prevented the coagulation of the blood, and 

 it was used as an anticoagulant in blood transfusions until 1915, when 

 it was found that some samples were highly toxic. Heparin was first 

 prepared from liver in 1916, but it was not used in medicine until it 

 was purified in 1933. Its action as an anticoagulant appears to be the 

 prevention of the conversion of prothrombin to thrombin. 



One of the early nineteenth-century transfusion experiments, which 

 may have been the earliest extracorporeal blood circulation of a living 

 organism, was performed by James Blundell (1790-1878) , an English 



