74 PATHOGENIC BACTERIA. 



micro-organisms that inhabit it. Thus he found that 

 cultures of his Bacillus graveolens, isolated from between 

 the toes, gave off the disagreeable odor characteristic of 

 " dirty feet." The Streptococcus pyogenes is also some- 

 times present. 



Surgeons formerly dreaded the air as the carrier of 

 infection to wounds ; they have now come to realize 

 that it is the incised skin that infects itself, and that 

 the most rigid disinfection is necessary to prevent it. 



b: Conjunctiva. — This is the most exposed moist sur- 

 face of the body and gathers micro-organisms from the 

 dust in large numbers. Its flora is almost unlimited, and 

 a work that I did some years ago 1 convinced me that 

 there was no fixed flora. A variety of pathogenic organ- 

 isms abound; thus it is quite a regular thing to find the 

 pyogenic cocci in health. The Bacillus xerosis, whose 

 relationship to xerosis is not determined, is common 

 upon this membrane. The researches of Hildebrandt 

 and Bernheim indicate that the conjunctival secretions 

 have a germicidal power. The number of micro-organ- 

 isms which I found would not suggest it. 



c. Nose and Respiratory Passages. — As bacteria are 

 widely distributed in the dusts suspended in the air, 

 they are necessarily taken into the nose with each re- 

 spiratory movement. The moist chambers of the nose 

 and the walls of the pharynx are splendidly adapted to 

 the function of catching and retaining these bacteria, and 

 probably very few of them succeed in penetrating as far 

 as the lungs. Those that do so in health probably meet 

 with very unfavorable conditions and are promptly dis- 

 posed of. If, however, the lung is in any way diseased, 

 we find that a variety of bacteria may present themselves 

 and aid in damaging the tissues. 



Thompson and Hewlett 2 estimate that 1500-14,000 

 bacteria are inspired every hour. As the expired air is 

 nearly always sterile, they sought to determine what be- 



1 Norris and Oliver's System of Diseases of the Eye, vol. ii., p. 489. 



2 Brit. Med. Jour., Jan. 18, 1896, p. 137. 



