In what is called spinal irritation all these phenomena may be met with, and are mixed up together in the most incongruous manner. Some inquirers have deceived themselves into the belief that the symptoms were capable of classification, and have even detailed examples of cases in which there was some pretension to scientific order and natural sequence; but in these instances they have, no doubt, been misled by their having put leading questions to per sons in whom the prominent condition was a disordered fancy, and by their having readily obtained answers in the affirmative. Take the patient's own account of symptoms, or put the leading piestions in such a form as to develop their incongruity, and no doubt need remain of the truth of what is here stated. There is often complaint of pain in the back, but its character, in place of being fixed, and local, and deep-seated, is diffused, superficial, and variable. Movement, at one time alleged to be impossible, is effected with perfect ease at another, when the attention is turned to something else : the slightest touch, when the question is put, will be-said to give pain, and yet firm pressure or a considerable jar at another moment is unheeded. This character alone is sufficient to distinguish such complaints of pain from those that are of real importance; the same remarks apply to the spasms and the paralysis which, each in.turn, may form the principal feature of the disorder : they may, by a little dexterity on the part of the observer, be proved to have their existence only in the exuberant fancy of the patient. If the distinctions in the use of terms just pointed oat had been clearly kept in view, we should probably never have had any doubts or confusion on this subject.
Chronic disease of the cord is a subject on which little can be said in a diagnostic point of view. The great evidence of its ex istence is to be derived from the paralysis which, sooner or later, always accompanies it ; but this symptom alone can give little information regarding the causes of its occurrence ; because, as will be shown in the sequel (see Chap. XV. § 2), one which really
acts only on a small fragment of the medulla, produces symptoms such as we should imagine indicative of disease of a much more extensive form.
The chief guide in determining the nature of the lesion is the order of sequence among the phenomena ; thus, in a very general way, it may be stated that pressure on the cord gives rise to feel ings of formication, tingling, heat and cold, &c., simultaneously with pain in the back : whereas in inflammatory action, even of a chronic kind, the pain is more usually associated, in the first instance, with spasm, and the sensation of numbness comes on at a later period. Both of these arc again distinguished from the common cases of paraplegia dependent on atrophy of the cord by the absence of pain in the latter condition altogether. Another circumstance which may serve for our guidance in this, as it does in other organs, is the knowledge which pathology gives of the relative position and extent of diseased action ; atrophy is con fined to the lower end of the cord ; inflammation is apt to diffuse itself widely ; tumors are most commonly found towards its upper extremity ; and each of these positions must of necessity be cha racterized by phenomena of different kinds.
I have said nothing of the means of distinguishing spinal arach nitis from inflammation of the substance of the cord, nor, again, of the difference in symptoms between inflammatory softening and hardening; they are far too uncertain to be laid down for the guidance of the student, who may rest quite satisfied if he can distinguish inflammation either of acute or chronic form from other lesions.