78 IMMUNOLOGY 



Garrod call attention to the accumulation of evidence showing tliat 

 individuals developing lobar pneumonia liave a pre-existing hu- 

 moral immunity and perhaps an allergy for the pneumocoecus. 

 This may seem paradoxical but would fit in with the allergic 

 hypothesis. 



The conclusion of Blake and Cecil that the primary focus occurs 

 at the hilus of the lung and that the infection spreads from the pri- 

 mary focus outward along the perivascular and peribronchial lym- 

 phatics has been challenged by Loescheke (1931), Terrell, Robert- 

 son, and Coggeshall (1933) and Gunn and Nungester (1936). The 

 newer work indicates that the primary focus is usually near the 

 periphery of the lung and that the infection spreads from the 

 periphery tow^ard the hilus in a wave of edema fluid that is swarm- 

 ing witli pneumoeocci and later invaded by leucocytes. Appar- 

 ently in the dermal pneumonia, as described by Goodner, edema 

 fluid gravitates down the flank of the ral)bit. 



In producing experimental pneumonia, Gunn and Nungester 

 .suspended the pneumoeocci in mucin for intrabronehial injection. 

 Tlie mucin provides a nidus in wliicli the pneumoeocci can begin to 

 multiply. The mucin holds them together and protects them from 

 phagocytes. These experimental results fit in ^vith one concept of 

 lobar pneumonia which postulates the existence of a nidus in which 

 the pneumoeocci can begin to multiply. Lindau suggests that such 

 a nidus consists of accumulated secretion which may be caused by 

 chilling of the body or other factors. It has l)een shown experi- 

 mentally that the application of cold to the skin causes hyperemia 

 of the respiratory tract and also increased mucous secretion. Since 

 juieumonia occurs quite frequently after operation on the upper 

 abdomen, it is suggested by Coryllos and Birnbaum (1928) that a 

 plug of mucous secretion in a bronchus is the nidus that aids the 

 bacteria to initiate the pneumonia. 



Factors Involved in Intestinal Infection. — Infections in the nose 

 and tln-oat may extend not only to the lungs, but also the sw^allow- 

 ing of pus, whether it be coughed up from the lungs or come as a 

 discharge from a sinus, etc., may lead to infections of the intes- 

 tinal tract. This occurs quite frequently in tuberculosis where 

 tuberculous sputum is swallowed. 



As material passes from the region of the tonsillar ring along 

 the intestinal tract, it is interesting to note that it encounters an- 



