ON THE FUNCTIONS OF THE BRAIN. 6j 



form. Every organ is in fact, then, an instrument whose constituent 

 elements remain identical, while their grouping grows more and more 

 involved in the same degree as the function itself displays more variety 

 and complexity. 



Reflecting, now, on the organic and physico-chemical conditions 

 required fur the support of life and the discharge of its functions, we 

 find that they are the same in the brain as in all the other organs. 

 The blood acts on the anatomical elements of all the tissues by supply- 

 ing- their indispensable conditions of nutrition, temperature, and humid- 

 ity. When a diminished supply of blood flows to any organ, its 

 activity of function declines, and the organ rests; but if the blood is 

 quite cut off, the elementary properties of the tissue slowly change, 

 while at the same time its function perishes. It is precisely the same 

 as to the brain's anatomical elements : as soon as the blood ceases to 

 flow to it, its nerve-properties are affected, as well as its function, 

 which gradually disappears, if the blood remains wholly withheld. A 

 simple modification of the temperature of the blood, in its pressure, 

 is enough to produce grave disturbances in the sensibility, the power 

 of motion, or the will. 



All the bodily organs present alternate states of rest and of activity 

 in which the phenomena of circulation differ essentially. Numerous 

 observations, made upon the most different structures, place these facts 

 beyond doubt. When, for instance, we examine the alimentary canal 

 of a fasting: animal, we find the mucous membrane that lines the inner 

 face of the stomach and intestines, pale and but little supplied with 

 blood; during digestion, on the contrary, we learn that the same 

 membrane is highly colored, and swollen with the blood which flows 

 energetically into it. These two phases of circulation, in a state of 

 rest and a state of activity, have been brought under direct investiga- 

 tion in the stomach of a living man. All physiologists recollect the 

 story of a young Canadian accidentally wounded by a leaden musket- 

 ball which struck him almost point-blank on the left side. The ab- 

 dominal cavity was laid open by an immense contused wound, and the 

 stomach, extensively perforated, allowed the food which he had last 

 taken, to escape. The patient was attended by Dr. Beaumont, a sur- 

 geon of the United States Army ; he recovered, but retained a fistulous 

 wound, opening with a circumference of about an inch and a half 

 through which different substances could be introduced, and the action 

 of the stomach easily examined. Dr. Beaumont, anxious to study this 

 remarkable case, employed the young man as a servant, after the com- 

 plete restoration of his health and particularly of his digestive powers. 

 He was able to keep him in his service for seven years, during which 

 he made a great number of observations of the highest interest to phys- 

 iology. On looking into the interior of the stomach while empty of 

 food, the lining membrane could be plainly seen, lying in uneven folds, 

 with its surface of a pale rose-color, motionless, and lubricated by noth- 



