410 Chapter XIII 



** soldering " in a purely mechanical fashion, without the intervention 

 of any preliminary proliferation of the epithelial elements. Thanks 

 to this very rapid obliteration the micro-organisms are prevented 

 from penetrating not only into the interior of the cornea, but into the 

 anterior chamber of the eye. 

 [430] It has already been pointed out that the ocular conjunctiva gets 

 rid of the introduced micro-organisms chiefly by removing them 

 mechanically and sending them through the lachiymal duct into the 

 nasal cavity. This, in turn, defends itself by making use of a similar 

 method. In his experiments on the Kiel red bacillus, inoculated into 

 the conjunctival sac of man. Bach demonstrated that in a very short 

 time these micro-organisms are carried into the nasal cavity. He 

 showed also that they do not remain long in the latter position and 

 that their number decreases hourly. 



Twenty-four hours after the introduction of these bacilli into the 

 conjunctiva none, as a general rule, are to be found in the nasal 

 mucus. This expulsion of the micro-organisms likewise takes place 

 by mechanical means, aided by the movements of the vibratile cilia. 

 It is evidently to this process that the mucous membrane owes its 

 relative freedom from micro-organisms. Frequently, when examining 

 the nasal mucus or when making cultures therefrom, one is astonished 

 at the small number of micro-organisms found in the nasal cavities 

 of persons in good health. Thomson and Hewlett^ have certainly gone 

 too far when they affirm that the upper regions [i.e. the Schneiderian 

 membrane] of the nasal cavity are, in almost 80 7o of cases, free from 

 micro-organisms. But it is certain that in these regions we do find a 

 small number only of the bacteria which exist in greater abundance 

 in the lower (cutaneous) passages of the nose. 



To explain this paucity of micro-organisms in the nasal cavity, 

 Wurtz and Lermoyez^ have assumed the existence of a bactericidal 

 property in the nasal mucus. They affirm that the anthrax bacillus, 

 after contact with this mucus for several hours, loses its virulence for 

 the most susceptible animals, and that several other micro-organisms 

 — the staphylococci, the streptococci, and the Bacillus coli — become 

 attenuated under the same conditions. Others who have studied 

 this question have come to a difierent conclusion. Thomson and 

 Hewlett found that the nasal mucus is not bactericidal, although 



^ [Med.'Chir. Trans., London, 1895, Vol lxxviii, p. 239] ; The Lancet^ London, 

 1896, Vol. I, p. 86 ; Brit. Med. Journ., London, 1896, Vol. i, p. 137. 

 2 Compt. rend. Soc. de hiol., Paris, 1893, p. 756. 



