l6 THE HORSE IN MOTION. 



carry all cases involving ethical or cesthetical questions, and form 

 might be confounded with color. To this pons asinorum all the old 

 writers on animal mechanics came. They would test vital force by the 

 laws governing the motion of the pendulum or those of gravity. If 

 physical science could establish the laws and solve all the questions 

 that arise in the investigation of vital phenomena, and algebraic expres- 

 sions could represent the unknown quantities, the task would be easy. 

 We could calculate the force of the right arm of a warrior as we could 

 the weight of his sword ; but when that arm descends, it falls with 

 more than the force of gravity. There is a power that must enter into 

 all our estimates of vital force, and that is the ivill. It cannot be 

 ignored in any calculation on animal motion ; and yet who can estimate 

 it, weigh it, and formulate it, as in the exact sciences .'' 



Thomas Starr King used to tell a story of a countryman who 

 attracted the attention of a traveller by the fine physical development 

 he displayed, and of whom he inquired his weight. " Well, stran- 

 ger," said he, " ordinarily I weigh two hundred and thirty pounds, but 

 when I am mad I weigh a ton." 



The progress that science has made in every department, and is 

 still making, is wonderful, and who can say where it will end ? But in 

 the knowledge of the laws which govern the origin of life, the vital 

 organs and their functions, of the nature of that force by which one 

 form becomes altered or modified by the altered conditions of its life, 

 it has made no progress since the days of Job. 



The whole question of life and vital force is still a great myster}', 

 although it is receiving at this time the concentrated attention of the 

 most intelligent naturalists of all nations. There are not many who 

 deny that organic forms may be modified within certain limits by arti- 

 ficial means. There are many who believe that all organic beings, of 

 whatever nature, had their origin in the most rudimentary element, as 

 a cell possessing certain inherent tendencies to develop by aggregation 

 into other and higher forms, unequally modified in various ways by 

 surrounding influences, with a tendency to variation by imperceptible 

 degrees in every direction, the useful variations favoring the existence 

 of the individuals possessing them. This idea has become familiar 



