4 



THE ANIMAL AS A MACHINE. 



ganisms having life, and which are less easily under- 

 stood, more difficult to study, and far less subject to 

 the modifying power of human action, than are those 

 of the first described class. 



(3) The forces of the soul and of the intellect — 

 those most wonderful and most mysterious of all known 

 forms of force — forces of the nature of which we know 

 nothing, and of the effects of which, actual and possible, 

 we have the least comprehension. 



By the study of the universe as it now exists, philos- 

 ophers are led to perceive that its present state is such 

 as would have resulted had the various forms of matter 

 with which we are surrounded, and of which we our- 

 selves are corporeally formed, and had other existences 

 which we suppose to form a part of our universe been, 

 at the beginning, so distributed and so placed in refer- 

 ence to the several kinds of forces that the former, 

 acted freely upon by the latter, should, by a continuity 

 of never-ceasing, ever-progressing change, take those in- 

 finite variations of growth, and all that inconceivable 

 variety of shapes, that have supposed to have been, by 

 the process called evolution," brought into the visible 

 universe.* 



Studying the accessible universe, as far as we are per- 

 mitted, in greater detail, we find that each of the var- 

 ious kinds of forces set at work to modify the position 

 and character of matter has a special part to play, a 

 peculiar work to do ; we find that the first class has a 



*As early as 1854 Helmholtz showed that the condensation of an 

 infinitely diffused nebulous mass of matter, to form the stellar systems 

 of the universe, by gravitation, was sufficient to furnish all existing 

 heat-energy, and a source of all that mechanical and other transformed 

 energy known now to exist. 



