478 IMMUNOLOGY 



and may discharge urine and feces, the nioveiuents of the ala 

 nasi and of the respiratory muscles indicate difficulty in breath- 

 ing. The animal usually coughs, jumps, staggers, falls over, and 

 makes rhythmical movements of the extremities and violent move- 

 ments of the muscles of respiration. It dies of asphyxia. If the 

 thorax is opened immediately, it will be observed that the lungs 

 are distended and cannot be made to collapse. The heart Avill 

 continue to beat for some time although Auer and Lewis showed 

 that heart block is present. They observed two or three auricu- 

 lar to each ventricular beat. The principal pathological finding 

 is the distention of the lungs with air. This was first observed 

 by Gay and Southard. Auer and Lewis conclude that this is the 

 immediate cause of death. In their opinion it results from a 

 tetanic contraction of the smooth musculature of the broncliioles, 

 producing stenosis. According to Schultz and Jordan, tliis is 

 localized in the secondary and tertiary bronchi. Auer says that 

 they claim: "the tetanic contraction of the nuiscle coat.s folds 

 the mucous membrane of this area into a plug which occludes the 

 lumen and thus brings about asphyxia." 



Protracted or Subacute Shock in the Guinea Pig. — When 

 the pig dies following prolonged or protracted shock, the lungs are 

 onlj^ partly distended. While this condition may be a contribut- 

 ing factor to death, it is possible that a drop in blood pressure 

 is also important. Another fairly constant finding in protracted 

 shock is a marked fall in body temperature. This is regarded 

 as a characteristic symptom by Braun, Friedberger, and others. 

 In addition to these findings, a prolongation of the clotting time 

 of the blood, a definite leucopenia, and a diminution in comple- 

 ment titer have been reported. 



The Dale Phenomenon. — In 1910 Schultz reported that if one 

 removes short segments of the small intestine from a sensitized 

 guinea pig and suspends them in a bath of Locke's or Ringer's 

 solution kept at body temperature, they will undergo specific 

 tetanic contraction when the homologous antigen is added to the 

 bath. Dale (1913) studied this phenomenon and found that al- 

 though Schultz used toxic doses of antigen, nevertheless, a specific 

 contraction can be demonstrated when nontoxic doses are em- 

 ployed. He suggests that excised uterine horns from young 

 virgin sensitized guinea pigs be employed instead of the loops 



