58 FROM DUST TO DUST. 



numbers, its average is adjusted by diminished supply of food on 

 the one side, or by increase of its enemies on the other. There is 

 thus a constantly shifting equilibrium, to which we are accustomed 

 to apply the term — the balance of Nature ; and, by this, every 

 species is maintained at a working point. I must not, however, 

 pursue this interesting problem any further, but proceed to the 

 "facilis descensus," which we find all too easy. 



We have now to consider micro-organisms in regard to their 

 nature as foes to health, as Pathogenic oxgdinhms producing Degen- 

 eration and Death. Leaving accidents out of consideration — and 

 these may be often the cause of the entry of pathogenic germs — we 

 may roughly define disease as a disturbance of vital phenomena, 

 using the word " vital " as symbolic of perfect life. It may be 

 some disarrangement of the alimentary or mechanical systems, 

 which, in many instances, will be found to depend upon some 

 remote bacterial action — such as, diarrhoea produced by souring 

 of milk, or ptomaine poisoning by preserved meat or vegetables, 

 or tubercular inflammation of a joint. We have also many diseases 

 caused by parasites of all sorts and sizes, from Taenia to Trichina 

 spiralis and Filaria. However, a great and ever-increasing num- 

 ber of diseases are now perfectly well ascertained to be the direct 

 result of pathogenic organisms. There is no need for me to 

 mention their names, as you are perfectly well acquainted with 

 them. I would like, however, to emphasise this fact — that disease 

 is not an "affliction," but, in most cases, the result of an ignorance 

 of, or a contempt for, those methods, which, for want of a better 

 name, we call '■ the laws of Nature." In other words, disease of 

 zymotic origin is " preventable ; " and it is a blot upon our so- 

 called advanced civilisation that it is not more prevented. Dirt 

 has been well described as "matter in the wrong place." Zymotic 

 disease is life in the wrong place. 



After the stage of disruption which we call Death has been 

 reached. Putrefactive organisms are the factors of change, causing 

 organic to be broken uj) into inorganic matter, in the process 

 called Animal decompositio?i. We must not forget that the world 

 has many scavengers by sea and land, such as sharks, vultures, 

 hycenas, and many others ; but these serve but temporarily to 

 arrest organic matter in its downward course, and leave the work 



