X plus Y equals Z, or the Sleeping Preacher of North Alabama – 1876 G W Mitchell
From the time of his first spell of cramping, as stated by Mrs Harlow, until the fall of 1859, he had a great many spells.  He knew nothing of them, generally at least, only as they were reported to him

X plus Y equals Z, or the Sleeping Preacher of North Alabama – 1876 G W Mitchell
Though at times he had spells of mental trouble, yet, in the main, he was quite cheerful.  But when he had been with us about 3 months, he was taken quite sick of a flux.  And when he had so far recovered as to be able to begin to walk, he was taken down with typhoid fever, and confined to bed again for several weeks.  During this confinement, he was seized with occasional convulsions, affecting at times his whole system, but especially his arms, chest, throat and tongue.  He also complained terribly of his head.  Often he would exclaim 'It surely will kill me'.  On one occasion he said 'My head feels like it has opened'.

X plus Y equals Z, or the Sleeping Preacher of North Alabama – 1876 G W Mitchell
During a camp meeting at Concord church, in September 1859, while he was engaged in an earnest public exhortation in the altar among the penitents, he was suddenly seized with a convulsion, fell to the ground, and passed into his peculiar sleep, from which he did not recover consciousness, except it might have been with short intervals, for many days, if not weeks.....While suffering in these spells he would cramp severely, with his head drawn until his face would be almost reversed; his hands drawn immovably, sometimes against his chest or throat; feet and legs twisted almost in the opposite direction from their natural position; and he would gasp as if every breath would be the last.

X plus Y equals Z, or the Sleeping Preacher of North Alabama – 1876 G W Mitchell
He may be taking part in social conversation, when all at once, if looking at him, you will see his eyelids fall and his head droop; at the same time making a slight but audible noise through his nose, which may be called a grunt, usually repeated in quick succession two or three times, and he is asleep.  The spell may continue for a few moments; a quarter, a half hour, or an hour, or a number of hours, a day, a night, or a day and night, or several days and nights, or a week, or even several weeks without an interval of consciousness.
As a general rule, the longer the spells are protracted the more intense are his sufferings.  So also when he is engaged in the more profound investigations, or is extending his vision to the greater distances; or his emotional powers are exercised intensely; under these circumstances, his head is always greatly affected.

X plus Y equals Z, or the Sleeping Preacher of North Alabama – 1876 G W Mitchell
X plus Y equals Z announced [to the author of the book] that he [intended to take] his leave of his 'casket' on the 5^th May 1876 and that after a lapse of time, not definitely stated (at least it has not been communicated to me) he will return again to finish his work.  Since that particular time, until this present, September 11^th, a period of more than four months, Mr Sanders has not, as he or anyone else knows, been the subject of one of his peculiar sleeps, even in the slightest degree.  As he was notified in that valedictory, he has had some paroxysms of severe suffering in his head, attended with some trouble in his chest; but aside from this, he is as other healthy men in body and mind.  For a time after the change took place, he was evidently greatly impressed with his new condition.  Much of his time he was absorbed apparently in deep and serious thought – seemed lonely – if not sometimes melancholy.  But after a time, he reacted and became quite cheerful; and since, says he enjoys himself, in this new condition, very much.

X plus Y equals Z, or the Sleeping Preacher of North Alabama – 1876 G W Mitchell
After 22 years of labour and suffering in and through the person of my casket, and for many years of that time both a mystery and reproach to others, I now come to the end of my first engagement; and will here leave off, in part, the work until my second and last coming, at which time I will reappear to finish up the great work for which I was intended.
My casket, I now come to address you, personally, before I depart.  You have been to me a greatly submissive servant, in suffering, in contempt, in wonder, in reproach, by night and by day, from year to year past.  You can never fully see all you have passed in this life until you see the life to come, when then you stand ready to fall back to dust, whence you came; and I leave forever.  I have given you many valuable lessons, and prevented you from many difficulties and sorrows.  I have shown you many friends, and many foes; what their strengths and how to treat them.  Together we have dwelt in peace and safety; but at your request, I leave you for a time.......
You will often and sadly miss me, when I am gone, but you cannot realise it now
My former charge, I leave you; and would say; Fill up the measure thereof that I may return to you the sooner
With Heaven's benediction I will now bid you adieu
X+Y=Z
5th day, 5^th month AD 1876 4 o'clock 8 minutes AM

X plus Y equals Z, or the Sleeping Preacher of North Alabama – 1876 G W Mitchell
I have been acquainted with him about 16 years.  He has complained ever since my acquaintance with him and he says for a number of years previous, with a continuous headache, though differing in severity at different times, often becoming excruciating; and until a year or two since, attended with violent lancinating pains in the chest, accompanied with great difficulty of respiration, which indeed I have often seen suspended for such a length of time as to induce me to believe it impossible that it could ever be restored; at length returning with a gurgling sound in the upper portion of the trachea.  In these extreme cases, the pulse is very feeble, and in frequency from 120 to such a celerity as to render it impossible to count it.  Extremities cold, temples throbbing violently, eyes surcharged with blood to such an extent that frequently the blood would trickle down the cheeks in drops.  These paroxysms are attended with very great nervous excitement

X plus Y equals Z, or the Sleeping Preacher of North Alabama – 1876 G W Mitchell
The length  of these paroxysms is quite variable, extending from a moment to hours and days, during which time he gets no natural sleep; the mind to all appearance being much more active than when in a normal condition; being all the time engaged in conversation or writing, of which he does a great deal, or some other active mental process.  In this condition he frequently complains of hunger and partakes of food.....he usually averages about 3 hours in 24 of natural sleep; yet the physical man does not seem to suffer from loss of sleep.  He looks as hearty as any man and weighs about 195 pounds.
This condition is not always attended with an unusual amount of pain, being  often very cheerful; at which times he is more than ordinarily communicative.
In all of his notes, letters and writings of every kind while in this condition he ignores the name of Sanders.  His signature is X+Y=Z

X plus Y equals Z, or the Sleeping Preacher of North Alabama – 1876 G W Mitchell
While in these sleeps, if left to himself, his thoughts are confined mostly to theology or medicine.  And though never having studied medicine, he seems, while in this mental state, to be very conversant with it; using the technical names, giving the properties, uses etc thereof.  He always examines the sick, ….making in writing a diagnosis and prescription... and I could mention a great many who have been relieved by his direction.  I have frequently had him to give me the exact condition of patients whom he had never seen, and who were miles distant.  His prescriptions frequently contain medicines which cannot be procured in this country, which he makes arrangements to import; showing his comprehensive view of Materia Medica

X plus Y equals Z, or the Sleeping Preacher of North Alabama – 1876 G W Mitchell
With regard to the abnormal exercises of his mental powers in seeing etc he has said; if you could see it, it may be imperfectly at least illustrated by the magnetic telegraph.
Suppose arrangements are completed to transmit a message on this line extending fifty miles, when the operator manipulates his keys the message almost instantly is correctly recognised at the receiving office.  Extend the line five hundred or five thousand miles, and the result is still the same; - so he says, his spirit does not leave the body and actually go to distant locations to get its cognitions pertaining to said localities; but extends its scope of vision etc and its cognitions are as certain as when it takes notice of things at hand.

X plus Y equals Z, or the Sleeping Preacher of North Alabama – 1876 G W Mitchell
Again that his vision is always, in this state, in direct lines, and in every direction, like the rays of light emanating from the sun.  That his head is, as it were, full of windows, so that he can see objects in any direction without changing the position of his head; yet he sees with more facility through his natural organs of sight.  And as hundreds of persons have seen him, when talking, reading or writing, all at once turn and with fixed gaze look in another direction – often right behind him – and tell what arrested his attention – speaking of some distant, or at least unseen, object by all but himself