ZYMOSIS 89 



mucosa affords a wide area for the growth of microbic 

 organisms, and a ready means of reaching a channel of 

 entrance to the cerebro-spinal cavity and third ventricle by 

 the pituitary apparatus. 



Thus, moreover, but not directly through the nervous 

 system, does the laryngeal, tracheal, and pulmonary mucosa 

 lend itself to the passage of hostile organisms into the 

 blood circulation with which it is overspread and inter- 

 penetrated, and where, especially in the calm vesicular 

 pulmonary recesses, in which rests the residual air, a fitting 

 repository is found for the lurking and breeding of unsus- 

 pected lethal bacillary organisms, in " miliary " proportions, 

 which are destined in the future to break their barriers, 

 join their contingents, and overrun and annihilate their 

 host. 



From the above it will be seen that air-borne bacteria 

 attack primarily the nervous system in the first two 

 methods of invasion, and the blood in the third and last ; 

 it must, therefore, follow that the organic media first over- 

 run must be the cerebro-spinal lymph and the blood 

 respectively, and that the germinal pioneer broods incubate 

 there, and thereafter traverse the invaded organism along 

 the lines of least resistance, and finally effect an exit by 

 eruption into neighbouring not yet invaded areas, or on 

 to the limiting or "bounding" surfaces of the body, 

 external and internal. The lines of invasion, the media 

 of incubation and growth, and the means and places of 

 exit of the peccant organisms, are, therefore, determined 

 by anatomical structure, physiological affinities, and histo- 

 logical continuity of circulatory facilities moreover, the 

 characters of the resultant morbid phenomena are conse- 

 quently moulded by the same genetic conditions, together 

 with the differing zoological, botanical, and other features 

 of the various bacteria. In this way the viri of such 

 varying diseases as influenza, diphtheria, and tuberculosis 

 effect an entrance into the systems of their victims, incu- 

 bate, develop, and remain, or are thrown out, according 

 to definite genetic conditions. 



Water-borne bacterial organisms have a more limited 

 "sphere of influence," but yet one sufficiently wide to 

 enable them to effect dire injury on whole populations 



