ON THE TRANSFUSION OF BLOOD. 685 



after decision by the Parliament, Du Chatelet, the deputy prosecutor, 

 publishes an edict proscribing it in the name of the law. What was 

 the real cause of the downfall of the system? That it rested on mis- 

 taken physiological ideas. The blood was still regarded as the sole 

 principle of instinct, intellect, and life. The physician who practised 

 transfusion could only defend it by hypotheses, and justify its em- 

 ployment by explanations and reasonings. The labors of our own 

 time alone can give it lasting life ; transfusion will revive two hun- 

 dred years later to a new and vigorous existence, for it will rest on 

 the best-established truths of physiology. 



The light thrown by Harvey upon the knowledge of life did not 

 give a complete account of the mechanism of our organization ; the 

 opening of an era of progress by grand discoveries awaited the coming 

 of Lavoisier, at the close of the last century. General physiology was 

 founded at that period, and the office and functions of the blood were 

 soon learned by degrees and clearly settled. Between 1815 and 1830 

 the history of transfusion passes into a new phase. Atwood, Blun- 

 dell, and Diffenbach, make it generally known by important works. 

 In France two eminent savants, Prevost and Dumas, devote themselves 

 to new researches, of which the "Annals of Chemistry," for 1821, 

 preserve the record ; but the transfusion of blood has made decisive 

 steps only within the last twenty years, due particularly to the labors 

 of a modern physiologist, Brown-Sequard. We shall sketch the bold 

 and interesting experiments he employed in attacking and dealing so 

 successfully with the most difficult problems of life ; the history of 

 physiology hardly presents a more exciting and instructive page. For 

 its full comprehension, the nature and functions of the blood must first 

 be explained. 



As it circulates within the vessels, the blood is to be regarded as 

 a fluid in which an innumerable quantity of colored corpuscles are 

 floating. On account of their shape, these little bodies are called glob- 

 ules, and they are invisible without the aid of magnifiers; in fact, 

 their diameter scarcely exceeds two ten-thousandths of an inch. The 

 vehicle of these globules has the scientific name of plasma ; the mat- 

 ters elaborated by the digestive apparatus, and the products of decom- 

 position of the tissues, are the essential components of this liquid ; 

 albuminoid substances, analogous to white of egg, fats, sugars, salts 

 of a mineral nature, appear in it under different forms, and constantly 

 repair it ; while the excretory ducts as constantly carry off from it 

 those particles that become useless to life. The elements of our tis- 

 sues have their nutrition kept up by a constant movement of supply 

 and withdrawal, new molecules replace the old ones, and acts of as- 

 similation and disassimilation find by turns in the plasma their point 

 of origin and completion. The blood-globule is nourished just as the 

 constituent parts of the glands, the muscles, the nerves, and the brain 



