92 Loc. cit.
93 Thomas Buzzard, Dis. of the Nervous System, London, 1882.
It must be borne in mind, however, that in those cases of congestion of the nerves, or neuritis, previously mentioned a quantitative increase may be found, indicating a hypersensitiveness of the peripheral nerve, and not necessarily of the spinal centres.
Poore94 states: “Thus we see that alterations of irritability” (he especially alludes to depressions) “accompany many conditions, both central and peripheral,” and “there is no necessity for assuming that central change exists in every case of altered irritability, and we have no warrant for such an assumption in the absence of independent evidence of central change.”
94 “Impaired Writing-power,” loc. cit.
Exactly what the alteration in the condition of the spinal cord is which probably occurs in many of these cases it is impossible to state, but the view that it is a nutritive change of the upper dorsal and lower cervical portion of the spinal cord (that is, when the arm is the part affected, as it is in all but the rarer cases) is quite attractive, the condition being secondary to a peripheral irritation in many cases.
Althaus95 considers that there is a “constriction of the small arteries, dilatation of the veins, and slight serous effusions compressing the nervous matter in the cervical spinal cord.”
95 Loc. cit.
Pain in the cervical and dorsal spine during work may be mentioned here as an evidence that some of the symptoms are due to central alterations.
Those few cases that exhibit great difficulty in performing one set of movements that requires a certain combination of muscles, but are able to use those same muscles in combination with others with ease, are difficult of explanation by the peripheral theory of the disease alone; but less difficulty is encountered if a superexcitability of the spinal centres is supposed to exist, for here we can imagine that when all the centres so affected are called into use, and only then, there will be an undue amount of nervous energy transmitted to the periphery, and disordered movement be the result.