326 PROTOPLASM 



If blood is well buffered, there should be little change in acidity. 

 How much may it, therefore, change with change in health? 

 This is a debated question. The evidence seems overwhelmingly 

 to support the statement that blood pH is not constant at all 

 times and under all conditions, yet some believe that disease 

 (e.g., cancer) involves no significant change in pH. Others claim 

 to have observed a change (to the alkaline) so marked (pH 7.44) 

 as to aggravate the disease. Probably both conditions exist, 

 depending upon the disease and the patient. Blood is certainly 

 well buffered but not against all conditions. 



The blood stream helps maintain an equilibrium in chemical 

 reactions in the body by keeping temperature constant and taking 

 care of a too acid or too alkaline condition, which it can do 

 because of its own highly buffered state and generally uniform 

 pH value. The blood maintains this uniform pH value by 

 adjustment between the red cells and the plasma. The red blood 

 cells take up acid and give off base to the plasma. In passing 

 through the lungs, they lose carbon dioxide and thus regain their 

 pH value. Naturally, other body functions materially con- 

 tribute toward maintaining an acid-alkali equilibrium. The 

 formation of acid in the body is compensated for by the excretion 

 of acid in urine, the formation of ammonia, and the elimination 

 of carbon dioxide through the lungs. As long as these reac- 

 tions are coordinated, the blood is of constant pH, and all 

 is well. 



MacDonald has shown that there is considerable evidence to 

 indicate a marked increase in the hydrogen-ion concentration 

 of the blood during fright, anger, anesthesia, and shock. It is 

 good medical technique to draw blood from an experimental 

 animal when it is in a quiet state and contented. The pH of 

 the blood of a frightened or excited animal is likely to be abnor- 

 mal. In practice, the animal should not even quiver from 

 nervous fear. It is maintained that a man in a high state of 

 emotion (from fear) has a low blood pH value (7.25), while when 

 he is quiet and calm, his blood may, a day later, rise to a pH 

 of 7.42. Hysteria and dilated pupils appear to be associated 

 with alkalosis, and psychasthenia with acidosis. According 

 to Cannon, hunger, fear, pain, etc., cause a diversion of blood 

 from the viscera to the muscles, thereby accelerating the metab- 

 olism of the latter (adrenalin is assumed to play a part) which 



