16 THE PRESENT CONDITION 



one substance, which is known to us as " Protein," a 

 complex compound of carbon, hydrogen, oxygen, and 

 nitrogen, which alone possesses the property of mani- 

 festing vitality and of permanently supporting animal 

 life. So that, you see, the waste products of the ani- 

 mal economy, the effete materials which are contin- 

 ually being thrown off by all living beings, in the 

 form of organic matters, are constantly replaced by 

 supplies of the necessary repairing and rebuilding 

 materials drawn from the plants, which in their turn 

 manufacture them, so to speak, by a mysterious com- 

 bination of those same inorganic materials. 



Let us trace out the history of the Horse in another 

 direction. After a certain time, as the result of sick- 

 ness or disease, the effect of accident, or the conse- 

 quence of old age, sooner or later, the animal dies. 

 The multitudinous operations of this beautiful me- 

 chanism flag in their performance, the Horse loses its 

 vigour, and after passing through the curious series of 

 changes comprised in its formation and preservation, 

 it finally decays, and ends its life by going back into 

 that inorganic world from which all but an inappre- 

 ciable fraction of its substance was derived. Its bones 

 become mere carbonate and phosphate of lime ; the 

 matter of its flesh, and of its other parts, becomes, in 

 the long run, converted into carbonic acid, into water, 

 and into ammonia. You will now, perhaps, under- 

 stand the curious relation of the animal with the plant, 

 of the organic with the inorganic world, which is 

 shown in this diagram. 



The plant gathers these inorganic materials together 

 and makes them up into its own substance. The ani- 

 mal eats the plant and appropriates the nutritious por- 



