Anaphylactic "Shock" in the Dog. 



3i 



The increased rapidity of respiration, sometimes spasmodic in 

 character, is transient and occurs after the fall in blood pressure 

 begins. It is thus secondary to the change in blood pressure and 

 possibly to be explained by the effect of the latter on the respira- 

 tory center. After the adjustment to low pressure is reached, the 

 respirations are of normal rhythm though shallow. No changes 

 in the lungs, which collapse upon opening the thorax, have been 

 found. 



Oncometric studies of the kidney, spleen and intestine have 

 shown that the volume of these organs is diminished. This 

 decrease in volume corresponds sharply in time and extent to the 

 fall of blood pressure. A cannula in the iliac vein shows a slight 

 increase in venous pressure (6 to 10 mm. of water). It is evident 

 therefore that the accumulation of blood occurs in the large venous 

 trunks of the abdomen and in the liver which at autopsy shows 

 intense congestion. 



Although our study is not complete, we consider the essential 

 feature of this vascular disturbance, as did Biedl and Kraus, to be a 

 loss of tone of the veins of the splanchnic area. It is of great 

 interest that Drs. Auer and Lewis explain the respiratory disturb- 

 ance in the guinea pig as due to a constriction of the smooth 

 muscle of the bronchioles while, in the ultimate analysis, 

 the disturbance in the dog is characterized by a paralysis of the 

 smooth muscle of the blood vessels. Although in the two animals, 

 different sets of smooth muscle are affected and affected in different 

 ways, it is significant that the phenomena of anaphylaxis which 

 are most readily studied by physiological methods are both char- 

 acterized by a disturbance of the functions of smooth muscle. 



Incidentally we have confirmed the observations of Biedl and 

 Kraus that anaphylactic shock closely resembles the blood pres- 

 sure changes following the injection of Witte's peptone and also 

 that, in the dog, the blood after the administration of the toxic dose 

 has lost its power of coagulation. 



All experiments were made upon animals sensitized to normal 

 horse serum injected in dose of five cubic centimeters subcuta- 

 neously The toxic dose was given intravenously after about twenty- 

 one days in amounts ranging from two to six cubic centimeters. 



