viii Journal of Comparative Neurology. 



The last mentioned experiments certamly add considerable prob- 

 ability to the theory that localization of auditory impressions consists 

 in the addition to them of sensations of movement. 



C. L. H. 



The Cortical Centre of the Muscular Sense.^ 



Dr. Starr offers a singular case in evidence that the centre of the 

 muscular sense is distmct from the centres of movement. It is re- 

 garded as settled that any defect in the tract conveying muscular sense 

 from the muscles to the brain cortex will produce a disturbance in the 

 power of coordination. Hitherto facts have been wanting to deter- 

 mine the actual position ol this tract in the cortex and the exact loca- 

 tion of the muscular sense centres. The following observation illus- 

 trates the possibility of producing an entire loss of muscular sense by 

 a limited destruction of the brain cortex, without prod ucing at the 

 same time any disturbance of motor power or tactile sensibility, and 

 determines the localization of the muscular sense centre for the hand 

 in the parietal region. 



The patient, a young man, suffered with intense headache, to the 

 left of, and somewhat behind the vertex, and from epilepsy. A heavy 

 fall during his fifth year, injured his head and was followed by uncon- 

 sciousness for several hours. Since the accident, while intelligence 

 and memory were good, he was easily agitated and subject to emo- 

 tional excitement and passion and lacked in power of application. 

 At the age of sixteen he had another fall on his head resulting in an 

 aggravation of these symptoms. With the accerbations of the head- 

 ache a maniacal condition was produced. These attacks occurred at 

 frequent intervals during five years. He was trephined at the seat of 

 injury and a small vascular tumor about three fourths inch in diameter 

 was found upon the surface of the brain. Some exploratory perfora- 

 tions were made and the wound made a rapid recovery, but immedi- 

 ately after the operation it was found that he had lost the muscular 

 sense in the right hand below the elbow, all voluntary guidance of the 

 hand being imperfect. The strength of the hand was unimpaired. 

 With eyes closed he could not determine the position of the hand, yet 

 tactile sense and temperature sense as well as that of pain were nor- 

 mal. After three months the muscular sense was fully recovered, it 

 was therefore considered that this particular effect was produced by a 



iStarr, M. a. The Muscular Sense and its Location in the Brain Cortex. 

 Psychological Review, II, I. 



