230 BIOLOGY OF PNEUMOCOCCUS 



the result of cultures taken after the death of the subject. As early 

 as 1905 Norris and Pappenheimer 1018 drew attention to the possi- 

 ble fallacy in making deductions from bacteriological findings at 

 necropsy, since organisms placed in the mouth after death were 

 conveyed to and could be recovered from the lungs by culture in 

 over one-half of the cases in which the post-mortem implantation 

 was made. 



The Carrier State 



Pneumococci abiding in the mouth and nasopharynx of healthy 

 persons — the chief portal of entrance of Pneumococcus to the 

 body — owe their presence either to direct or indirect contact with 

 other persons harboring the organisms in their oral or nasal cavi- 

 ties, or to previous pneumococcal disease in the same individual. 

 The mere presence of these pathogens in the body is insufficient to 

 incite disease; it is the constitutional factors of the host which 

 determine whether the invaders are to remain as innocuous mem- 

 bers of the usual bacterial population or whether they are to aban- 

 don their life of saprophytism and act as malignant parasites. In 

 the absence of such depressing conditions as alcoholism, chilling, 

 the exhaustion of fatigue, undernourishment, avitaminosis, or the 

 contributory influence of previous or concomitant disease, Pneu- 

 mococcus may develop none of its pathogenic potentialities. 



The upper respiratory passages of the new-born babe, accord- 

 ing to Gundel and Schwarz, 575 are sterile at the time of delivery 

 and may remain so for a few hours after birth. Then on the second 

 or third day pneumococci may appear, the type and number de- 

 pending upon the quantitative occurrence of similar organisms in 

 the immediate environment, especially in the oral cavity of the 

 mother. The infant as it enters and passes through childhood re- 

 ceives from its fellows and elders contributions from their bacterial 

 flora. In a systematic study of the incidence of pneumococci in the 

 upper respiratory passages of normal persons, largely schoolchil- 

 dren, Gundel (1933), 569 by repeated tests made every four weeks 



