EVOLUTION AND THE AFTER-LIFE. 47 



tliougbt for the thougluful of all limes. Gradually these thoughts 

 have taken form, and a science of psychology has grown up, engaging 

 in its investisrations the efforts of the ablest minds. 



It may not be reasonable to suppose that any being, unless it be 

 the Infinite, should perfectly comprehend itself. How far man is from 

 being able to claim such knowledge may be inferred when we consider 

 that, although he has been upon the earth so many thousand years, it is 

 less than three centuries since he began to understand even his physical 

 organization, or comprehend such simple facts in his own physiology 

 as the process of digestion and the circulation of the blood. It is 

 only within the present century that the functions of the nervous sys- 

 tem began to be understood, and only within the last few years that 

 its relations to mental activity have been intelligently studied. With 

 so many points in regard to the functions of the material body only re- 

 cently understood, and even now but imperfectly known, is it strange 

 that our psychical i-elations should be even less perfectly compre- 

 hended ? 



A recent writer' has pointed out the fact that each epoch of intel- 

 lectual activity and enlargement, as marked by the discovery of new 

 truths in Nature, has been accompanied or directly followed by better 

 modes of investigation and more scientific views in psychology ; and 

 not only so, but the methods emj)loyed and the results obtained in 

 psychology have had direct relation to the methods and results in 

 physical science. As mathematics and the laws of motion gave us 

 Descartes and Hobbes, scientific medicine or the " science of observa- 

 tion " Locke, the vibratory theory Hartley, and chemistry the elder 

 Mill, so geology and the doctrine of evolution have been potent in 

 influencing the methods and results obtained in psychology by Bain 

 and Herbert Spencer. And as each advance in psychology has had 

 reference to the methods in physical science which have preceded it, 

 so do we find that the doctrine of evolution, which in its general aspect 

 at least has given direction to the scientific thought of the present gen- 

 eration, has also been the doctrine which has thrown most light upon 

 the constitution and action of mind. 



It is not the object of this paper to discuss the doctrine of evolu- 

 tion, but simply in the light of that doctrine, as generally understood, 

 to present such facts as science has prepared for us relative to the 

 development of mind, and its manifesting organs in the gradually- 

 ascending series of animal forms. 



The organ of all psychical manifestation is the nervous system, 

 and the material of which it is composed is substantially the same, 

 whether in animals of a hio;h or a low organization. It is of two 

 kinds, the gray matter^ usually found in nodules or masses of greater 

 or less bulk, called ganglia, and the white matter, usually found in 



* " The Development of Psychology," Westminster Review, and Popular Science 

 MosTHLY, July and August, 18 74. 



