206 Dr. E. L. Mellus. Experimental Degenerations [June 13, 



V. " Experimental Degenerations following Unilateral Lesions 

 of the Cortex Cerebri in the Bonnet Monkey (Macacus 

 Smicus)." By E. LINDON MELLUS, M.D. Communicated by 

 Professor V. HoRSLEY, F.R.S. Received May 1, 1895. 



(From the Pathological Laboratory of University College, London.) 

 (Abstract.) 



The object of this investigation was to trace by the so-called 

 anatomical method the degeneration resulting from minute lesions of 

 the motor area of the cortex cerebri through the brain and spinal 

 cord, to locate the path of the conducting fibres in the internal 

 capsule and elsewhere, to follow them as far as possible to their 

 destinations, and by such control observations to check off the results 

 obtained by previous excitation experiments. 



Method Pursued. 



The animal selected for these experiments was the bonnet monkey 

 (Macacus Sinicus). and the lesions were made in the motor area of the 

 left hemisphere. The records are here presented of degenerations 

 resulting from fourteen (14) successful operations, three being lesions 

 of the hallux centre, four of the thumb centre, and seven of four 

 separate centres in the facial area. The animal being etherised the 

 skull was opened under 'strict aseptic precautions, and the centre to 

 be removed located by stimulation with a weak faradic current. A 

 small portion of the cortex (generally about 16 sq. mm.) embracing 

 this centre was then excised, care being taken to remove with it a 

 portion of the underlying corona radiata, thus ensuring the removal 

 of all the cortical cells. The scalp wound was closed with horse-hair 

 sutures and covered with borated cotton held in position by collodion. 

 The wound in every case healed by first intention and but slight and 

 transient paresis resulted. The animals were killed in from 10 to 

 35 days after the operation, the brains and cords hardened in Miiller's 

 fluid and stained by the Marchi method. 



Degeneration following the Hallux Lesions. 



The portion of the cortex removed in these cases was taken as 

 nearly as possible from the centre of the triangular space at the upper 

 extremity of the ascending frontal convolution formed by the longi- 

 tudinal fissure and the fissure of Rolando, and extending down the 

 convolution to the posterior extremity of the superior frontal sulcns. 



Numerous degenerated association fibres, both coarse and fine, were 

 found passing to the central convolutions down to the level of the 



