The human brain : its structure, physiology and diseases. With a description of the typical forms of brain in the animal kingdom / by Samuel Solly.

Date:
1847
Catalogue details

Licence: Public Domain Mark

Credit: The human brain : its structure, physiology and diseases. With a description of the typical forms of brain in the animal kingdom / by Samuel Solly. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    70/736 (page 42)
    arrangement; but, when we consider the remarkable m- tricacy and minuteness of the whole structure in these animals, and recollect how lately even the two roots them- selves have been discovered, it may be well permitted us to doubt if the entire anatomy of these nerves is yet known. It is seen on inspection that the nerves are attached, as has already been stated, to the ganglions, which bodies are themselves connected by a few delicate longitudinal tln-eads, which also extend from the uppermost ganglion to the brain. Now from the analogy of the vertebrated animals, it may be assumed that these threads consist in part of longitudinal commissm^es, by which the ganglia are com- bined in their functions, and in part of true sensiferous and volition filaments, which terminate in the brain. In de- scending the scale, from the most perfect animal to the lowest classes in Avhich a symmetrical nervous system exists, it is seen that exactly as the motions of the body become independent of the brain, the nerves contain a larger proportion of those fibres (the true spinal) which terminate in the substance of the spinal cord, and fewer cere- bral. But it is most erroneous to assert, as some authors have done,* that in the invert^brated animals the spinal cord is not directly continuous either with the brain or with itself: on the contrary, wherever there is a grey mass in the head, however minute, which corresponds in office with the brain, a connection with the nerves through the medium of the spinal cord is indispensable to the exercise of that voluntary control over the motions of the body which in these instances always exists. In the invertebrate animals thus endowed, there is in fact no difference in the type of the cerebro-spinal axis, when contrasted mth that of the Vertebrata ; there are innume- rable varieties of form, but in every instance the essential structures have a real existence.! Dr. William Carpenter followed Grainger in this path, and in the fullest and in the most philosophical manner has brought the anatomy of the MoUusca to elucidate this * Fletcher's Rudiments of Physiology, PL 2 b. p 87. f Observations on the Structure and Functions of the Spinal Cord, by E. D. Grainger. 1837.