ON THE FUNCTIONAL ACTIVITY OF NERVE CELLS. 715 



published in the ' Journal o£ Physiology,' and in [the ' Proceedings of the 

 Royal Society,' 1897 and 1898. In addition the following reports have 

 been received. 



APPENDICES. 



I. On Structural Alterations observed in Nerve Cells. 

 By W. B. Warrington, M.D. 



A paper was published in the ' Journal of Physiology,' vol. xxiii., on 

 the structural alterations observed in nerve cells : — 



(1) Of the anterior horns of the spinal cord after section of the 

 posterior roots. 



(2) After division of the axons belonging to them. 



Summary of Part I. 



Records of observations made on eight cats and one monkey are 

 given. 



These observations show that after sections of several posterior roots, 

 from the fifth to the ninth post-thoracic inclusive, a considerable per- 

 centage of obviously altered cells are found : their distribution in the case 

 of the cat is practically limited to the seventh and eighth segments, and 

 especially to the posterolateral group of cells in those segments. 



In the monkey the upper part of the seventh segment is picked out. 



The efiect is to a very slight extent a crossed one, and presents the 

 remarkable feature that more aflected cells were found in the sixth seg- 

 ment of the crossed side than on the side of the lesion. 



In the cervical region, in one case, similar but slight changes were 

 found limited to the seventh segment ; in the other the spinal cord was 

 practically normal. 



The significance of these results and of their limitation to certain cell 

 groups is discussed, and the view adopted that the structural changes 

 correspond to the altered functional state of motor cells deprived of the 

 afierent impulses which impinge upon them. 



Summary of Part II. 



Observations were made on eight cats, one monkey, and on material 

 supplied from the autopsy room (I am indebted for the material in the 

 case of the monkey and one cat to Professor Sherrington). 



The observations show that — 



1. Distinct and easily recognisable changes in nearly all the cells of a 

 segment of the spinal cord are found on the side of the lesion after section 

 of an anterior root. 



2. Similar but less marked changes follow division of the facial nerve, 

 and still less distinct alteration after division of the oculomotorius nerve. 



3. The fate of such altered cells and the ultimate condition of the 

 nucleus of origin are not yet definitely ascertained. 



4. The age and nature of the animal experimented on is a factor iu 



