84 iMMUNOLOGt 



of an excess of alkalies is called alkalosis. Neither is desirable and 

 hence both are to be avoided. 



Finally it should be recalled that the liver, in addition to 

 other things, is quite potent as a detoxifier of proteins ; the spleen 

 and lymph glands are efficient filters for pathogenic bacteria 

 because they form part of the reticulo-endothelial system. The 

 bone marrow supplies red cells and white cells, the former endowed 

 with a potent oxygen carrier that is also a good buffer and the 

 white cells are phagocytic in nature. The vascular system and 

 the vasomotor mechani.sms aid in maintaining a normal distribu- 

 tion of blood, and tliese and many otlier factors help maintain 

 the noi'mal integrity of every tissue coll in the body. 



Prenatal vs. Postnatal Immunity.^ — The importance of normal 

 physiological factors in resistance is empliasizcd by the discovery 

 of Woolpert and his associates (1938, 1940, 1941) that fetal 

 susceptibility of guinea pigs to influenza virus is changed at birth 

 to resistance. This suggests that in some unknown way the 

 immunity is associated with postnatal circulatory and respiratory 

 readjustments. 



Importance of Considering the Body as a Whole. — Since the 

 cells of tlie body are protoplasmic in nature and since protoplasm 

 is an intricate mass of dynamic colloidal SA^stems, it is very 

 essential to consider the "body as a whole" in attempting to 

 understand infection and resistance. It would seem obvious that 

 while circulating antibodies are of value in the body's defense 

 against infection, except for antitoxins their role and relative 

 importance have been considerably exaggerated. In diagnosis, 

 however, they have won for themselves a place of great importance. 

 Underlying Principle of Therapy. — When a patient with a 

 beginning pyogenic infection is treated by a physician, the idea 

 behind the therapy is to maintain the local tissue mechanisms of 

 defense at an optimum and thus encourage localization or prevent 

 extension by any of the possible routes of dissemination. In the 

 case of pelvic peritonitis the head of the bed may be elevated, 

 thus enlisting the forces of gravity while other measures are being 

 instituted. Generalized peritonitis is exceedingly dangerous owing 

 to the large area of peritoneal surface through which absorption of 

 toxic substances and infectious agents occurs and also because of 

 the danger of bowel paralysis and complete suppression of urine 



