414 IMMUNO-CATALYSIS 



f. A Comparison of the Syndromes of Histamine and Anaphy- 

 lactic Shock. Several physiological changes which occur in anaphylaxis 

 and histamine shock are commonly shared. In the guinea pig, in both 

 cases, there is the spasm of the bronchial smooth muscle, causing 

 suffocation and death, spasm of the smooth muscle of the gastro- 

 intestinal tract, uterus, ureters and gall bladder. In the dog, the mus- 

 cular walls of the efferent hepatic veins constrict, producing localiza- 

 tion of the blood in the capillary spaces of the liver. In the guinea 

 pig in both cases, there is capillary dilatation and capillary perme- 

 ability causing localized edema. 



Another similarity between histamine and anaphylactic shock is the 

 protection of the animals against the action of both by antihistamine 

 drugs. 



A characteristic feature of anaphylactic shock is the failure of the 

 formation of blood-clot. This failure is absent in histamine shock. 

 Another difference between the two phenomena is that the severity 

 and persistence of the distention of the dog's liver with lymph and 

 blood in anaphylaxis is far greater than that occasioned by histamine 

 shock. These differences speak against the identity of the underlying 

 mechanism in the two instances, though the characteristic similarities 

 of certain syndromes suggest that certain factors are common to the 

 two phenomena. 



6. Metabolic Changes in Shock 



In fully developed shock there is a diminution in the circulating 

 blood volume and a cutting off of the supply of oxygen and nutrients to 

 the tissue. It is observed that there is first an increase in blood sugar; 

 it then decreases reaching a state of hypoglycemia, especially in the 

 terminal stages of shock. This may be due to depletion of liver glycogen 

 in rats in tourniquet shock, in rabbits in gravity shock, and in hemor- 

 rhagic shock, and to a marked increase in the utilization of carbo- 

 hydrate by the peripheral tissues (Wilhelmi, 1948). Depletion of 

 glycogen in shock is accompanied by increased carbohydrate utilization, 

 increase in blood lactate and pyruvate and a striking rise in the ratio 

 of lactate to pyruvate and a shift toward anaerobic metabolism in the 

 tissues. Outpouring of lactate from the tissues may be correlated with 

 a marked fall in arterial blood plasma carbon dioxide and blood pH. 



