APPARATUS FOR PHYSIOLOGICAL USK 231 



that I have drawn on the blackboard a line which I doubt 

 not is perfectly familiar to you. That line expresses with 

 very great accuracy the law of falling bodies ; for its curva- 

 ture is such that it could only have been produced by a 

 body moving with ever-increasing velocity. 



FIG. 2 Extemporised apparatus for investigating the course of a falling body in 

 its descent, a a in each figure are two corks held by clamps, by which a glass 

 rod, g, is supported vertically at a short distance from the surface of the revolv- 

 ing cylinder c. The falling body ft (a block of brass pierced by a tube of the same 

 metal) slides freely on the rod. At its upper end a thread is attached by which it 

 is prevented from falling until the proper moment. The cylinder having been 

 put in rapid rotation, a match is applied to the thread, 6 falls and writes by the 

 style, w, the line shown in the right-hand figure. 



I will give no further illustration derived from physics, 

 for my purpose is to show you the application of the 

 method to vital motion. The characteristic phenomena 



