458 ME, J. L. CLAEKE ON THE GKET STTBSTANCE OE THE SPINAL COED. 
roots of the nerves, or escape through the anterior columns; while those from their 
posterior ends extend backwards to different distances, and form a contmuous stra m 
of fibres along the lateral margin of the grey substance: some of them jom the fibres 
which radiate from the centre, and contribute in succession to form the bumfles whic 
escape as a network through the antero-lateral column; others extend as & as the 
posterior cornu, and seem to be continuous with the posterior roots which escape 
through the postero-lateral fissure. The rest of the posterior roots partly descend towards 
the centre of the anterior cornu, and partly cross the posterior comu diagonaUy ul 
connexion with a chain of cells, to be continuous with the transverse commissui-e. n 
the cervical enlargement (fig. 45), the cells of the anterior comu are more numerous 
and more diversified in shape; some of them send processes towai'ds the anterior com- 
missure, but a great number have no apparent connexion with it. 
In my first communication on the spinal cord, I stated that the posterior roots of the 
spinal nerves are attached exclusively to the posterior white columns. I have smce 
found that the same assertion was made by RoLAiimo : he says, “ tutti i fill nervosi e e 
radici posteriori se staccano esclusivamente dai cordon! posteriori del gmn umco o spi 
nale- cio che puo essere comprovato in varie e differenti maniere*.” Stillixg demes 
the feet, and maintains that in the lumbar region a few fibres traverse the postenor part 
of the antero-lateral column. I have again carefully gone over the ground, m the cord 
both of Man and different animals, and find that my statement is correct. Stilling has 
probably confounded nerve-fibres with the blood-vessels which traverse the posterior part 
of the antero-lateral column much in the way that he represents. 
APPENDIX. 
[Added during the printing of the Paper.] 
Convinced of the superiority and value, in many respects, of my method of anatonucal 
research, I will here describe it more fully, together with the modifications which I 
have lately introduced in some stages of the process, and the precautions necessai-} to 
be observed in order to ensure success. 
The structure or part intended for examination should be as fresh as possible, and 
cut into portions as small as is compatible with the end in liew. These portions I 
formerly hardened by means of a mixture of one part of spiiit of ufine and three parts of 
water which at the end of twenty-four hoiu's was replaced by a fresh mixture of equa 
parts of spirit and water, and this again after the same interval was replaced by pure 
spirit, which ought to be renewed every five or six days. At the end of ten to fourteen 
days the medulla is sufficiently hard for making sections, which ai'e then subjected to 
the following process for the purpose of inducing transparency. The sections are first 
placed in a mixture of one part of strong acetic acid, and four, five, or six of spirit, for a 
* Oj}. cit. p. 82. 
