192 PSYCHOLOGY. 



conditions could be possible for the delicate calling of the 

 sensibility into play than are realized in the minutely grad- 

 uated rotations and firmly resisted variations of pressure 

 involved in every act of extension or flexion. Nevertheless 

 it is a great pity that we have as yet no direct testimony, 

 no expressions from patients with healthy joints accident- 

 ally laid open, of the impressions they experience when the 

 cartilage is pressed or rubbed. 



The first approach to direct evidence, so far as I know, 

 is contained in the paper of Lewinski,* publiylied in 1879. 

 This observer had a patient the inner half of whose leg 

 was anaesthetic. When this patient stood up, he had a 

 curious illusion about the position of his limb, which dis- 

 appeared the moment he lay down again : he thought him- 

 self knock-kneed. If, as Lewinski says, we assume the inner 

 half of the joint to share the insensibility of the corre- 

 sponding part of the skin, then he ought to feel, when the 

 joint-surfaces pressed against each other in the act of 

 standing, the outer half of the joint most strongly. But 

 this is the feeling he would also get whenever it was by any 

 chance sought to force his leg into a knock-kneed attitude. 

 Lewinski was led by this case to examine the feet of cer- 

 tain ataxic patients with imperfect sense of position. He 

 found in every instance that when the toes were flexed aifid 

 drawn upon at the same time (the joint-surfaces drawn 

 asunder) all sense of the amount of flexion disappeared. 

 On the contrary, when he pressed a toe in, whilst flexing it, 

 the patient's appreciation of the amount of flexion was 

 much improved, evidently because the artificial increase of 

 articular pressure made up for the pathological insensibil- 

 ity of the parts. 



Since Lewinski's paper an important experimental re- 

 search by A. Goldscheider t has appeared, which completely 

 establishes our point. This patient observer caused his 

 fingers, arms, and legs to be passively rotated upon their 

 various joints in a mechanical apparatus which registered 

 both the velocity of movement impressed and the amount 



* ' Ueber den Kraftsinn,' Virchow's Archiv, Bd. Lxxvii. 134. 

 t Archiv f. (Anat. u) Physiologie (1889), pp. 369, 540. 



