250 ELEMENTARY PHYSIOLOGY. [XXIV. 



elbow. The application of cold to the trunk of 

 a nerve does not cause a sensation of cold. 



9. Tactile delusions. 



Cross the second finger over the first or the 

 third over the second, and place between their 

 tips a small marble (or any solid round body a 

 little larger than a pea) so that it touches the 

 radial side of the first, and the ulnar side of the 

 second finger-tip. On gently rolling the body 

 about, a sensation as if of two distinct bodies 

 will be felt. 



The same delusion is experienced if the tip of 

 the nose be gently rubbed with the tips of the 

 fingers so placed. 



Experiments 6 and 7 will need the assistance of a 

 second person, 





