MODEBN IDEAS OF SANITABY ECONOMY. 



63 



putrefactive decomposition, that we have no stronger mode of 

 producing identity of action. 



Let us suppose an illustration : — The body is well, and 

 decomposition goes on, producing certain pretty well known 

 results by the action of life and all its subservient forces. One 

 takes cholera, and decompositions go on in him also, but with 

 dijBTerent results. Instead of nitrogen being retained by the 

 kidneys, they cease to act, and the bladder is empty ; instead 

 of the lungs decomposing the carbonaceous compounds, the 

 gall bladder is filled with them, and the breathing is difficult. 

 The foeces take the nitrogen. Its analogy to a reverse fer- 

 mentation, or a diverted one, is complete. But there is no 

 power of recomposing what was destroyed. It is a splitting 

 up of particles of the bodies into parts; what is begun quietly 

 goes on till all the material is worked up. If it passes to 

 another person, it is a further illustration of the same action. 



10. But a ferment acts by self-destruction. When it is 

 done, what becomes of it? It converts the material next it, 

 if capable, into a ferment also. We therefore conclude that 

 infections increase according as the material to feed them 

 increases ; in other words, they convert all impure matter into 

 infection, because it is fermentable in a particular way. In 

 this way, then, various ferments would produce various sub- 

 stances. Or a substance putrefied might go into plague, fever, 

 or small pox, just as the parts of the body do. Filth, there- 

 fore, is a conveyancer of disease, taking the lead of any 

 infection which happens to have the reins in its hand at the 

 time. No wonder, then, if all diseases disappear before a 

 great disease, — one great ferment banishing the others. There 

 cannot, in one liquid, be both the mucous, acetic, and alcoholic 

 fermentations at once. 



11. But they may come in succession ; so after one disease 

 another may arise on its remains. Is this the explanation of 

 the rise of new diseases, or the history of the progress of some 

 we ^now, which go on from stage to stage ? 



