THE NERVOUS SYSTEM. 377 



The nerves in question arise, without exception, not from the columns 

 or fibrous substance, out of which they proceed, but all penetrate more 

 or less deeply into the central parts, and all probably become connected, 

 some not till they have decussated like the trochleares, with definite 

 parts of the gray substance, which Stilling not inappropriately terms 

 nerve nuclei (accessory nucleus, for instance). It is the floor of the 

 fourth ventricle, and of the aqueduct of Sylvius, which are more par- 

 ticularly concerned in this respect, since all the nerves above named, at 

 least in part, extend to them. The more minute consideration of these 

 relations may be seen in Stilling's Work, and in " Mikroskop. Anatomic," 

 II. 1, pp. 458-462. 



Although a favorable judgment cannot be given upon Stilling and 

 Wallach's work on the spinal cord, I am still very far from disposed to 

 look down upon Stilling's anatomical writings in general, as would seem 

 to have been the fashion for some time past. I am much rather of 

 opinion, in which R. Wagner also coincides, that we have great reason 

 to thank this author for his works on the medulla oblongata and pons 

 Varolii ; for although there are some thfngs in them which cannot be 

 maintained, and sufficient attention is not paid to the elementary con- 

 stituents, still it cannot be denied that they contain a mass of important 

 facts. I have tested, if not all, still the most important of Stilling's 

 statements, and have found them almost all fully confirmed, and am, 

 therefore, glad to take this opportunity of naming him, as the observer 

 to whom we are indebted for the first accurate investigation of the 

 course of the fibres in the central organs. I would also here, add : 1, 

 that in further investigations of this kind, chromic acid, or chromate 

 of potassa, is to be preferred to alcohol, particularly also when caustic 

 soda is cautiously employed for the tracing of the course of the nerve- 

 fibres in the gray substance thus rendered transparent; and, 2, that in 

 conjunction with lower magnifying powers, the most powerful should be 

 employed, and the relations of the elementary constituents should also 

 be otherwise accurately investigated. 



The question as to the origin of the nerves in the medulla oblongata, 

 presents itself as one of the most difficult nature. Most anatomists 

 have hitherto been content to trace the roots of the nerves as far as one 

 or the other column ; but this is not sufficient. All the nerves enter at 

 least once, or even several times, into gray substance, in which, and no- 

 where else, are their origins to be sought for. Now, it must be con- 

 fessed, that through Stilling's great pains, the fruits of which I can, as 

 it may be said, fully confirm all the ten pairs of nerves at present 

 under consideration have been traced in their roots, as far as perfectly 

 definite points of the gray substance ; but now comes for the first time 

 the further question : do they commence in these situations, or do they 



