Abstract from notes on the minute structure of the spinal cord / by John B. Trask.
- John Boardman Trask
- Date:
- 1860
Licence: Public Domain Mark
Credit: Abstract from notes on the minute structure of the spinal cord / by John B. Trask. Source: Wellcome Collection.
Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)
5/18
![[3] I do not propose writing a method of preparation now, for the subject is still a matter of experiment with me as to which is the best method, and we had better wait for a final success or failure, than attempt to expound a pro- cess that is immature. My experiments on the spinal cord of the sheep, were commenced at the first dorsal vertebra, and carried downward to the first lumbar ; and then from the place of beginning they were carried upward to the first cervical vertebra. These were the preparatory steps in the experiments, and were conducted in rather a rapid manner, for the purpose of obtaining the position of certain parts which had been previously determined upon for examination, and which were found not to present an entirely uniform 'phase and position in all parts of the cord intermediate between the points named. After obtaining through the above means the approximate relations of the parts, I then commenced at the second cervical vertebra, and carried the sections from this to the first dorsal. This portion then is the only part of the cord examined by me with care, and in the present paper I shall attempt to describe but a part of this space, viz.: that included between the upper surface of the second, and the lower surface of the fourth cervical. The first series of experiments were made upon transverse sections for the purpose of obtaining the relations of position of the nerve elements (?) thus displayed, and those of the. columnar and central portions of the organ. THE CEKTKAL CANAL OF THE CORD. In using the term canal, in this place, it is done for the purpose of con- forming to the use of a word expressing an opening, or cavity in the central portion of the spinal cord. Strictly speaking, we are not justified in its use in this particular, for it has not as yet been shown that this opening is not a closed sac, but to avoid confusion the term is preferred here until further investigation shall develop its true character. The fact is patent that many of the most eminent anatomists, even of the present epoch, have denied the existence of the central canal of the spinal cord, and Kolliker is among the number of living observers who have taken that position. On page 655 of the Encyclopedia of Anatomy and Physiology, the same doubt is expressed by Mr. Todd. He says If such a canal exist, it must be extremely difficult to demonstrate, as I have never after numberless examina- tions, been able to see it. In transverse sections of the spinal cord which have been dried upon glass, there is sometimes an appearance which may be attributed to the presence of a minute canal; but I should be more disposed to ascribe it to the patulous mouth of a blood vessel which had been divided in making the sections, for it is by no means constant even in difi'erent regions of the same spinal cord. The situation some have assigned to this supposed canal, is between the gray and white commissures; but Stilling and Wallach place it in the gray matter. It is obvious that an artificial separation of these layers, which is easily effected, and more especially while the prepara- tion is being dried, would give rise to the appearance of a canal upon a trans-](https://iiif.wellcomecollection.org/image/b21160211_0005.jp2/full/800%2C/0/default.jpg)
