

1863.] 6/3 



The fibres are not offsets or outgrowths which grow centrifugally 

 from different adjacent cells and then join or anastomose with one 

 another, hut they result, on the other hand, from the moving away 

 from each other of cells which were originally continuous ; so that a 

 very thin fibre of foT) (Tol)^ f an mc ^ * n diameter, and perhaps 

 three or four thousandths of an inch in length, represents the 

 broader and shorter bands or cords of communication which existed 

 at an earlier period of development, when the cells were much closer 

 together. 



It has been stated that nerve-cells do not exist in the white matter ; 

 but numerous cells are present in this tissue for the distance of 

 perhaps the sixth of an inch or more beneath the grey matter. I 

 do not propose now to enter into detail ; the arrangement of the 

 cells and fibres will be accurately represented in drawings ; for it is 

 not possible for me to convey an accurate idea of the structure of 

 this elaborate tissue by description. I may be permitted to offer the 

 following general conclusions resulting from observations upon the 

 grey matter of the convolutions of man, the sheep, cat, and dog. 



1. The numerous nerve-cells of the grey matter are all connected 

 or give origin to at least two fibres. 



2. These fibres, wide near their origin, gradually diminish in 

 thickness until they are not more than the ! * Q th f an mcn m 

 diameter. 



3. The granular matter said to be so abundant in the grey matter 

 consists of fine and very delicate nerve-fibres, which are easily broken 

 down when thin sections of this soft tissue are submitted to micro- 

 scopical examination without special preparation. 



4. It is probable that the cells of the grey matter of the convolu- 

 tions are connected together ; but in the adult the cells are not often 

 connected with those cells which are situated nearest to them. 



5. There is no reason for supposing that the nerve-cells, here or 

 elsewhere, influence any nerve-fibres save those which are struc- 

 turally continuous with them. 



