THE PATH OF EVOLUTION 



ing almost unhindered through the thick soft tissues 

 that lie between. In either case they render infor- 

 mation and help to the Surgeon from unexpected 

 and unknown sources that would have seemed like 

 the fairy tale of a magician's power, if told of or pre- 

 dicted a few years ago. 



The properties of the Rontgen rays are involved in 

 those of the Kathode rays, for before escaping through 

 the glass tube they were part thereof. The rays 

 emitted from the Kathode consist of a mixture of 

 varied nature. The larger part, those which become 

 visible by impinging on the side of the tube, are 

 stopped in their course by the walls thereof, which they 

 heat by their impact ; they are deflected by a magnet. 

 They are emitted at right angles, perpendicularly to 

 the surface of the Kathode plate. If it is deeply con- 

 cave, they can be brought to a focus therein, where 

 they will develop intense heat, and will even fuse 

 Iridium, the most intractable of metals. They are 

 not permeable to glass, but will pass through a thin 

 plate of aluminum if forming a part of the tube wall; 

 will escape into the air and there show a diffused light. 

 They are thought to carry material corpuscles nega- 

 tively electrified. They appear to be of the identi- 

 cally same character irrespective of the nature of 

 the gas in the tube from which they originally came, 



J. J. Thompson and other investigators suggest 

 190 



