214 THE PRINCIPLES OF IMMUNOLOGY 



The fall in blood-pressure appears in anaphylactic shock in the dog 

 and cat but is not so highly characteristic of the reaction in the guinea- 

 pig or rabbit. Biedl and Kraus described the condition, and it has 

 since been studied extensively. Pearce and Eisenbrey note that it 

 amounts to a fall of from 20 to 30 mm. mercury in the dog and believe 

 it to be due to vaso-dilatation, particularly of the splanchnic area, due 

 to action upon the nerve endings rather than upon the muscle. Schultz 

 was of the opinion that the fall in pressure is due to direct action upon 

 the heart by the toxic agent. He expressed the opinion that in the cat 

 the fall in general pressure is due to vaso-constriction in the pulmonary 

 circuit so that the right heart cannot empty itself. Eisenbrey and 

 Pearce in a further study on dogs found that the functional activity 

 of the myocardium is not primarily affected, that there is no satisfactory 

 evidence of pulmonary vaso-constriction and that the later changes 

 in the myocardium with the fall in general pressure result from incom- 

 plete filling of the heart consequent on the accumulation of blood in 

 the larger venous trunks, particularly of the splanchnic area. Simonds 

 finds that with the fall in arterial pressure, there is a fall in pressure in 

 the superior vena cava and a rise in portal vein pressure, associated 

 with an increase in the volume of the liver. Upon examination of the 

 hepatic vein of the dog the vessel shows a very heavy musculature as 

 compared with that of the herbivorous animals, and Simonds con- 

 cludes that spasm of the hepatic vein and its tributaries explains the 

 phenomena observed. Manwaring and subsequently Voegtlin and 

 Bernheim had previously found that exclusion of the liver from the 

 circulation prevented the appearance of anaphylactic shock, observations 

 well in accord with Simonds' hypothesis. However, Pelz and Jackson 

 excluded the entire abdominal circulation, and in spite of this demon- 

 strated broncho-constriction and marked fall in blood-pressure. Thus, 

 although numerous factors may play a part, the only fact that we can 

 bring forward as generally accepted is that the fall in arterial pressure 

 is associated with peripheral vaso-dilatation. Davis and Petersen 

 observed an increase in the volume of lymph for a short time imme- 

 diately following injection and again for a longer period beginning 

 about one hour after injection. The antiferment increases in the lymph 

 without any change in the blood serum. 



There can be no doubt that the gaseous interchange in the 

 convulsive phases of anaphylactic shock is increased. Varying reports, 

 however, have appeared as to the influence of anaphylactic shock upon 

 nitrogen metabolism. Major found an inconstant decrease of nitrogen 

 output in rabbits during shock, but this increased in the animals that 

 survived the immediate shock to such a degree as to exceed the intake. 

 Zunz and Gyorgy found a definite increase in amino-acids, which 

 Jobling, Petersen and Eggstein confirmed, with the additional informa- 

 tion that the total non-coagulable nitrogen is increased. Hisanobu 

 found a marked increase of urea nitrogen, as well as of the non-urea 

 and amino-acid nitrogen. He concludes, as would also be apparent 

 from Major's work, that there is an abnormally rapid destruction of 



