476 THE POPULAR SCIENCE MONTHLY. 



right we should impose laws on the nature of which we are the 

 resultant. If we would make a durable work, our first thought 

 should be to learn those laws, in order to submit ourselves to 

 them more exactly. We should regard it as an axiom that, given 

 the human organization, there could be only one correct solution 

 in any special case of utilization of force. The problem is to find 

 that solution ; and to reach this there is, in my opinion, no shorter 

 way than to study in each sport those select subjects, or experts, 

 who have succeeded by practice in excelling in some specialty. 

 We should for that study arm ourselves with precise means 

 of investigation, which will explain the essential principles of 

 their movements, and take these principles as the rules of 

 education. Although these rules have not yet been established, 

 it is not because experts have been wanting ; but the most trained 

 eye can not perceive the subtle differences between the means 

 which experts employ for reaching perfection of movements. 



It has been necessary, in order to make a further advance in 

 this study, to create processes which have unveiled a new world 

 of facts. It has been the constant purpose of M. Marey to seek, 

 besides purely subjective sensations, certain experimental data, 

 and thus forestall eternal discussions on obscure points of physi- 

 ology, in which the fundamental basis itself of discussion facts 

 was wanting. The services which the photochronographic 

 method has rendered to biology are well known ; in the present 

 case, again, it is invoked as a means of correcting errors. The 

 photographic methods in use at the physiological station give, in 

 short, the complete solution of the analysis of motions, however 

 rapid and complex they may be. 



By comparing photographic representations of different sub- 

 jects or of the same subject at different stages of movement, we 

 may exactly define the manner in which they proceed, seize the 

 slightest differences that distinguish their motions, and perceive 

 the least modifications that are produced in their turn. If these 

 all relate to the same type in the process of perfectionment, we are 

 authorized, after eliminating individual variations, to take and 

 teach what Nature has revealed to us. We can thus study expert 

 subjects under two points of view, for the qualities which they pre- 

 sent are derived partly from their structure and partly from their 

 education. Everybody walks, runs, and jumps ; but there are few 

 who have a passable gait unless they are trained to it. In short, 

 we learn to walk, run, and jump, as we learn all the rest. We 

 can not well learn alone ; and it is one of the essential objects of 

 physical education to perfect the normal gaits as well as all the 

 movements in general. It is furthermore important to extend 

 the individual's life of relation and to accustom it to various 

 movements which are of indisputable utility for defense and for 



