ON TUBERCULOSIS 195 



We may regard it from this point of view as axiomatic, 

 that no disease germ can develop at the expense of 

 absolutely healthy and physiologically active tissue, and 

 that, therefore, the immunity of absolutely healthy people 

 is thus secured, even though they be exposed to the attack 

 of infectious disease, if they but unremittingly attend to 

 the removal from their bodies, externally and internally, 

 of the effete materials on, and in, which such organisms 

 can alone live and move and have their being. 



Consistently with this view of the genesis and progress 

 of tuberculosis, we, therefore, find the period of incuba- 

 tion of the disease to vary according to the condition of 

 health and the character of bodily hygiene of its subject 

 at the time of infection and during an indefinite period 

 thereafter ; moreover, we find that the infection frequently 

 proves abortive, as when the pathogenic germs are success- 

 fully resisted by an impervious wall of physiologically 

 perfect tissue structure and perfectly dynamically endowed 

 tissue elements, or when these germs have been mechani- 

 cally removed or therapeutically destroyed or neutralised 

 by proper systemic hygienic agencies by, or in, conjunction 

 with properly devised artificial means ; in other words, by 

 the rational and commonsense union of natural and arti- 

 ficial agencies, climatic and therapeutic, such as changed 

 environment, improved ingestion, and facilitated egestion, 

 whereby the vis medicatrix nature is assisted in resisting 

 and overcoming the onward progress of pathogenesis or 

 pathological cell proliferation at the expense of the normal 

 or physiological metabolism. 



Pulmonary tuberculosis, or the most prevalent form of 

 the disease, is, we may conclude, generally due to air-borne 

 infection, the germs of which by inspiration are carried 

 into the remotest recesses of the vesicular textures of the 

 lungs, and deposited on the surrounding exfoliating 

 endothelium, or in the exfoliated and unexpectorated 

 debris, to which it adheres, and in which it grows, forming 

 by subsequent accumulation and arrested removal, it may 

 be, caseated or calcified particles or masses, or miliary 

 tubercles, and ultimately, it may be, attacking the now 

 somewhat imperfectly vitalised surrounding endothelium 

 and adjacent pulmonary inter-vesicular textures, which it 



