W. B. WHERRY 879 



these antibodies — obstacles which prevent their coming in contact with the parasites. 

 Here, again, Wright' has performed pioneer work in analyzing the situation. 



Recently Wherry^ has suggested that even if a parasite is otherwise equipped to 

 thrive in the body of a host it will not do so and produce disease unless there is some 

 chemical interaction between the parasite and the host which brings about a separa- 

 tion of water from its combination with the tissue colloids, thus putting into solution 

 food for the bacteria. This freeing of water in the tissues (edema) may result from the 

 production of amines. Infections which spread rapidly are accompanied by marked 

 edema. When a series of heat-killed bacterial antigens are injected into man, some 

 give rise to local urticaria, others do not. The production of urticaria is taken to in- 

 dicate susceptibility. 



1 may summarize briefly the effect of the local-tissue edema on the further growth 

 of the parasites and upon the defensive mechanism as follows: (a) It provides dis- 

 solved food for the bacteria, (b) It dilutes the antibodies, (c) It immobilizes the phag- 

 ocytes, for leukocytes are dependent on contact for motility, (d) It prevents or delays 

 the absorption of antigenic substances that might lead to immunity, (e) It dilutes 

 anti-leukoprotease, and so permits the freed leukoprotease to digest the fixed tissue, 

 and hastens abscess formation. 



Wright^ found that there was a loss of anti-tryptic power and a diminution in the 

 alkalinity in the edematous fluid at the site of infection with CI. welchii, both in man 

 and in animals. In the blood he found a diminution of alkalinity and an increased 

 amount of anti-trypsins. In other words, the lack of the anti-ferment and the reac- 

 tion at the site of infection were unfavorable to phagocytosis. 



Every effort, therefore, should be directed toward reducing the edema by the use 

 of hypertonic salines, glucose, incision, etc. And in the case of open wounds anti- 

 bacterial substances should be drawn into the focus by establishing an external flow 

 of serum by Wright's method. Wherever possible as many of the parasites as can be 

 reached should be killed by the use of dyes, etc. Often the successful reduction of the 

 edema at the beginning of an acute inflammation may by itself so favor the normal 

 defense mechanism that healing follows promptly. 



In attempting immunization against any infection it is most important that the 

 right antigen be selected. This is a simple matter where only one bacterium is con- 

 cerned, provided that it is certain that the single species found is the only one present. 

 In mixed infections the right antigen can be selected by preparing separate heat-killed 

 suspensions of the species present and testing the patient by intradermal inoculation. 

 Those antigens which give rise to urticaria or urticaria and congestion are chosen as 

 the ones concerned in the infection. Heat-killed bacteria make good antigens,-' and 

 subcutaneous inoculation gives rise to the production of opsonins. ^ 



The question of dosage should not be based on anyone's personal experience re- 



' Wright, A. E., and Colebrook, L.: loc. cit.; Wright, A. E.: Studies on Immunizatmi. London: 

 Constable, 1909; Wound Infections. New York: WilUam Wood & Co., 1916; "Treatment of Infected 

 Wounds by Physiologic Methods," Brit. M. J., i, 793. 1916; Proc. Roy. Soc, 114, 576. 1927. 



2 Wherry, W. B.: /. Infect. Dis., 41, 177. 1927. 



3 Wright, A. E.: Lancet, 1, 21. 1917. 



■• Taylor, F. E.: J. Hyg., 15, 163. 1915. sNoon, L.: ihid., 9, 181. 1909. 



