1866] WRITINGS OF JOSEPH HENRY. 459 



state of permanent equilibrium by bringing matter into 

 crystalline forms or into a condition of simple aggregation, 

 while under its mysterious influence the particles of matter 

 are built up into an unstable condition in the form of or- 

 ganic molecules. While therefore we may refer the changes 

 which are here produced, or in other words the work per- 

 formed, to the expenditure of the physical powers of heat, 

 chemical action, &c., we must admit the necessity of some- 

 thing beyond these which from the analogy with mental 

 phenomena, we may denominate the directing principle. 

 Although we cannot perhaps positively say in the present 

 state of science that this directing principle will not manifest 

 itself when all the necessary conditions are present, yet in 

 the ordinary phenomena of life which are everywhere 

 exhibited around us, organization is derived from vitality, 

 and not vitality from organization. That the vital or direct- 

 ing principle is not a physical power which performs work, 

 or that it cannot be classed with heat or chemical action, is 

 evident from the fact that it may be indefinitely extended 

 — from a single acorn a whole forest of oaks may result. 



The principles of which we have here endeavored to give 

 an exposition are strikingly illustrated in the transformation 

 of the egg when subjected to a slightly elevated temperature. 

 The egg of a bird for example consists, as we know, of a 

 congeries of organized molecules or vesicles, enclosed in a 

 calcareous shell, thickly punctured with minute holes, through 

 which the oxygen of the air can enter, and vapors and gases 

 escape. Let us observe the difference of changes which take 

 place in two newly-laid eggs, one of which is not possessed 

 with vitality, and the other is endowed with this mysterious 

 principle. Both of these eggs are in a condition of power, 

 the carbon, hydrogen, nitrogen, sulphur, &c., of which their 

 organized molecules are composed, are in a state of unstable 

 equilibrium and ready, when set in motion by a slight in- 

 crease of temperature, to rush into the more stable compounds 

 of carbonic acid, vapor of water, &c., by chemical attraction. 

 While the eggs are in an unchanged condition they possess 

 the same amount of what is called potential energy, which 



