412 POISONS, CONTAGIONS, MIASMS. 



the constituents of some one organ of the body, a 

 substance or substances exist in a state of chemical 

 action, to which the vital principle of the diseased 

 organ opposes no resistance. The component parts 

 of the organ must suffer changes simultaneously with 

 the starch, so that the more starch is furnished to it, 

 the more energetic and intense the disease must 

 become ; while if only food which is incapable of 

 suffering such transformations from the same cause 

 is supplied, and the vital energy is strengthened by 

 stimulant remedies and strong nourishment, the 

 chemical action may finally be subdued, or in other 

 words, the disease cured. 



The conversion of starch into sugar may also be 

 effected by pure gluten, and by dilute mineral acids. 



From all the preceding facts, we see that very va- 

 rious transpositions, and changes of composition and 

 properties, may be produced in complex organic 

 molecules, by every cause which occasions a disturb- 

 ance in the attraction of their elements. 



When moist copper is exposed to air containing 

 carbonic acid, the contact of this acid increases the 

 affinity of the metal for the oxygen of the air in so 

 great a degree that they combine, and the surface of 

 the copper becomes covered with green carbonate 

 of copper. Two bodies, which possess the power 

 of combining together, assume, however, opposite 

 electric conditions at the moment at which they come 

 in contact. 



When copper is placed in contact with iron, a pe- 

 culiar electric condition is excited, in consequence 

 of which the property of the copper to unite with 

 oxygen is destroyed, and the metal remains quite 

 bright. 



When formate of ammonia is exposed to a temper- 

 ature of 388° F. (180° C.) the intensity and direction 

 of the chemical force undergo a change, and the 

 conditions under which the elements of this com- 

 pound are enabled to remain in the same form cease 

 to be present. The elements, therefore, arrange 



