DEP/DUA/1/46/18 (Normalised version)

Thomas McKay

(1789)

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N^o2. Thomas McKay at 30.

This case formerly pronounced to be a paralytic affection under that form which has name of Hemiplegia.

And indeed so distinctly marked by diminishment of power both of sensation & motion in whole of left side, but particularly in leg & arm that any farther remarks on diagnosis altogether unnecessary.

May however observe that this like other modifications of palsy admits of considerable variety both with respect to appearance & cause.

Sometimes entirely under form of loss of sense, motion continued unimpaired.

Sometimes again entirely in loss of motion sensation continues as acute as ever.

And in some, although it must be allowed in rare instances total loss of sense in one side of body, total loss of motion in other.

These some have explained from supposed affect of different kind of nerves.

That one kind viz [subsists] to [purpose] of sense another to those of motion.

This supposition however liable to many objections [here] out of place

Many only observe that in my opinion much better explained from affect occurring in different nerves.

And each as it were to be considered as partial paralysis.

When loss of sense disease in cutaneous nerves

When loss of motion in those supplying muscles.

But much more frequently as in the case before us both affected at same time.

When however thus represent affection of nerves as cause of palsy, must yet add that do not consider it as universal cause.

For with respect at least to loss of motion am inclined to think that this may sometimes depend on [condition] of muscle fibre itself.

That a muscle may be capable of action a certain degree of irritability or disposition to [approximation] of parts on application of a stimulus is required.

And this irritability some have supposed to be primary [internal] quality of muscle fibres altogether independent of nervous power.

Hence when exhausted or destroyed in muscles paralysis or loss of power of motion, must occur independent of nerves.

How far this [doctrine] strictly well founded here foreign to our business to [inquire]

May only observe that for my own part disposed to adopt opinion of those who contend that irritability in muscle fibre, is supplied by nervous energy with which are impregnated.

And no difficulty in conceiving that this may be case with them, although irritability exists in vegetables which have no nerves.

But whether irritability depends on nervous energy or not, cannot be a doubt, that the nerves are conductors of sense & motion.

That is without free communication by nerves, no volition of mind can produce muscular action.

No impression on body, can produce a sensation in mind.

Free communion may be interrupted from different causes.

But particularly either from compression or from condition of nervous power to be moved.

Compression of nerve may take place either in course or at origin.

But from former even when on large branch or plexus can give only a very partial disease.

Hence then as far as compression operates in present instance, may conclude it to be at origin or within brain.

But when this the case may conclude that will also affect condition of nervous power.

That will give rise to a want of mobility in nervous energy, or what commonly distinguished by title of state of Torpor.

This can readily suppose to occur in fluid communicated by certain nerves while that of others possess usual mobility.

For if nervous fluid secreted, brain can I think have no hesitation in viewing it not as one but a number of secreting organs.

Hence nerves arising from one part may be in very different condition from those arising from another.

This then idea of pathology or peculiar morbid condition, occurring in present case.

I suppose a cause of compression to have originally acted on nerves supplying left side of body at origin.

And that from affected state of secretion had induced torpor in fluid communicating to these.

Cause of compression suppose to be now in great measure if not entirely removed.

But torpor in considerable degree still to remain.

On this idea have had recourse to electricity.

And have directed it under form of sparks drawn from all parts most affected.

Electricity I need hardly observe one of most powerful & penetrating stimulants with which are acquainted.

While others externally applied act only on cutaneous nerves, this penetrating to those which deeper seated.

And gives equal impression on extremity of nerves in muscles as in skin.

Hence we see that operates as powerful stimulus inducing contraction in these.

And indeed after a muscle altogether insensible to other stimulants, may yet be contracted by electric spark.

But is not from action on extremes of any nerves that can expect, to restore sense or motion, where depends on Torpor.

Impression however thus made at least if Torpor not very great necessarily communicated to origin.

And indeed is alone by impression given in this manner that can have access to origin.

Influence of stimuli however may thus be communicated to any particular part of brain.

And in this manner, state of Torpor in fluid supplied to particular nerve may be removed.

Is not however from use for short time that such a change to be expected.

Can only expect much from continuing with considerable perseverance.

And am for my own part convinced that electricity has often failed from want of assiduity in application.

Am far indeed from pretending to say, that with utmost assiduity, will be successful in every case of palsy.

Many, perhaps even majority totally incurred by any means we can employ.

In others electricity will have remarkable affect at first, but after certain progress disease will become static.

And will be found totally inadequate to complete cure.

But in not a few, even where progress hardly obvious for long time, will yet in end be product of best affects.

And in my opinion should never despair of deriving farther benefit as long as patient feels power of sensation & motion increase after being electrified.

Or while by any changes in state of disease, have evidence of its not being static.

Encouraged by these circumstances then naturally led to persist in employment.

And am in hopes, that notwithstanding unfavourable opinion which some have of this mode of cure, present case may yet afford us strong instance of benefit to be derived from electricity in Paralysis.