996 TECHNIQUE OF EXPERIMENTATION IN ANAPHYLAXIS 



example, there is a fall in the venous pressure synchronous with the fall in the arterial 

 blood pressure.' On account of the absence of valves in the portal vein the portal 

 blood pressure is readily measured by means of a cannula in one of its larger col- 

 laterals. In dogs, the portal blood pressure is usually doubled during the first two 

 minutes of acute anaphylaxis.^ 



RATE OF BLOOD FLOW 



Anaphylactic changes in the rate of blood flow in certain organs have been de- 

 termined by means of a cannula in the efferent vein. In dogs, for example, the normal 

 rate of blood flow through a lo-cm. intestinal loop is about 20 cc. per minute. This 

 is reduced to about 2 cc. per minute by the end of the first ninety seconds of ana- 

 phylactic shock, with a further reduction to about 0.2 cc. per minute by the end of 

 the third minute.' 



BLOOD VOLUME 



The only methods of estimating changes in total blood volume thus far applied 

 to anaphylaxis are methods based on observed changes in hemoglobin content, 

 erythrocyte count, and plasma concentration.^ Interpretation of such data is difficult 

 on account of the marked reduction in the number of circulating red blood corpuscles 

 due to capillary and sinusoidal stasis, and to possible changes in the amount of 

 circulating protein due to altered capillary and parenchymatous permeability. 



CAPILLARY STASIS 



Anaphylactic stasis in the hepatic sinusoids and intestinal capillaries is readily 

 demonstrated by ordinary histological methods. In the canine liver, for example, the 

 sinusoidal plugs, described by Simonds,^ sometimes persist for several days after re- 

 covery from the shock. 



CAPILLARY PERMEABILITY 



The marked edemas of certain organs in acute anaphylaxis suggest possible 

 changes in capillary permeability. Petersen and Levinson^ have attempted to demon- 

 strate such changes by determinations of the quantitative changes in thoracic 

 lymph proteins during canine anaphylactic shock. The most convenient organs for 

 the study of such reactions, however, are the isolated canine lungs. Quantitative 

 study of the fluid escaping from the trachea of perfused hypersensitive canine lungs 

 shows that during anaphylactic shock in the blood-free lungs the capillary endo- 

 thelium offers no demonstrable resistance to the outward passage of serum proteins.'' 

 Larger colloidal molecules are held back. 



' Simonds, J. P.: Am. J. Physiol., 65, 512. 1923. 



2 Simonds, J. P.: ibid.; Manwaring, W. H., Brill, S., and Boyd, W. H.: /. Immunol., 8, 121. 1923. 



3 Manwaring, W. H. : unpublished data. 



■i Simonds, J. P.: Am. J. Physiol., 72, i. 1925. 



5 Simonds, J. P.: /. Infecl. Dis., 24, 297. 1919. 



* Petersen, W. F., and Levinson, S. A.: J . Immunol., 8, 349. 1923. 



'Manwaring, W. H., Hosepian, V. M., and Thomson, W. L.: J .A.M. A., 82, 542. 1924. 



