DECOMPOSITION. 423 



The sugar of milk is non-fermenting, and can be procured from whey by 

 evaporation. 



DECOMPOSITION. 



We have seen that animals and plants are composed of many different 

 substances, and so it will be at once understood that these substances can 

 be separated from each other, and then the decomposition of the body will be 

 completed. When the sap sinks or dries up in plants they are dead. When 

 our heart ceases to beat and our blood to flow we die, and then, gradually but 

 surely, decay sets in. There is no fuel left to keep the body warm ; cold 

 results, and the action of oxygen of the air and light or water decays the 

 body, according to the great and unalterable laws of Nature. " Dust thou 

 art, and unto dust shalt thou return," is an awful truth. The constituents 

 of our bodies must be resolved again, and the unfailing law of cJiemical 

 attraction is carried out, whereby the beautiful organism, deprived of the 

 animating principle, seeks to render itself into less complicated groups and 

 their primary elements. 



This resolution of the organic bodies is decomposition, or " spontaneous 

 decomposition," and is called decay, fermentation, or putrefaction, according to 

 circumstances. The Egyptians, by first drying the bodies of the dead (and 

 then embalming them), removed one great source of decay viz., water, and 

 afterwards, by the addition of spices, managed to arrest putrefaction. 



Fermentation is familiar in its results, which may be distilled for 

 spirituous liquors, or merely remain fermented, as beer and wine. Fusel oil is 

 prepared from potatoes, rum from cane sugar, arrack from rice. The power 

 of fermentation exists in nature everywhere, and putrefaction is considered 

 to be owing to the presence of minute germs in the atmosphere, upon which 

 Professors Tyndall and Huxley have discoursed eloquently. 



Plants are subjected to a process of decomposition, which has been 

 termed "slow carbonization," under certain circumstances which exclude 

 the air. The gases are given off, and the carbon remains and increases. 

 Thus we have a kind of moss becoming peat, brown coal, and coal. The 

 immense period during which some beds of coal must have lain in the ground 

 can only be approximately ascertained, but the remains found in the coal- 

 measures have guided geologists in their calculations. 



Having already mentioned some products of distillation, we may now 

 close this portion cf the subject and pass on to a brief consideration of 

 minerals and crystals. We have left many things unnoticed, which in the 

 limited space at our disposal we could not conveniently include in our sketch 

 of chemistry and chemical phenomena. 



