Behold, then, an intuition whose correctness the experience of forty years has not contradicted.

It is hard to imagine the joy I felt at my discovery produced and verified in a single day by so many examples, differing so greatly one from another and of such diverse interest.

All the emotions of this extraordinary and fertile day had so over-excited my imagination that I had great difficulty in calming my poor brain, and far from being able to enjoy the rest which I so much needed, I was a prey to wakefulness in which the turmoil of my ideas at one time made me fear that I was going mad.  I then felt for the first time the frailty of the instrument of thought in regard to the faculty which rules and governs it.

In brief, I was—­thanks to my double discovery—­in possession of a law whose deductions ought to touch the loftiest questions of science and art,—­and I was enabled thenceforth to affirm upon strong and irrefragable proof that the thumb, in its double sphere of action, is the thermometer of life as well as of death.

Episode III.

The day after that which had been so fruitful both in emotions and discoveries, a thousand recollections tumultuously besieged my mind and still disturbed me.  I saw that if I could not contrive to classify them in strict order of succession, I should never be able to derive any practical value from them.  I therefore took up link by link the chain of events of the previous day, but in inverse order.  That is, I began my course where I left off the day before, and thus proceeded toward the Tuileries to end at the Medical School.

At the retrospective sight of all that merry, noisy little world, of all those fat, cheerful nurses, careless and laughing as they were, of those mothers each so tenderly expansive in contemplation of her child, so happy in its health and strength, so joyous and so proud of its small progress, the recollection of a phenomenon which I had not at first observed struck me with all the force of a vivid actuality.

I should say, by the way, that it is much more to the strength of my memory than to the present observation of facts, that I owe these remarks.  Stability is the sine qua non of the things one proposes to examine, and the memory must possess the singular power of communicating fixity to fugitive things, permanence to instantaneousness, and actuality to the past.

Now, the phenomena of life occurring with the rapidity of lightning can only be studied retrospectively; that is to say, in the domain of memory, except to be verified if the attention, free from all other preoeccupation, allows us to seize them on the wing once more.  The remark suggested to me by memory seemed all the more interesting because it formed in a new order of facts a flagrant opposition to the opinion formulated by my masters under the title of theory.  Thus nature once more proved to me that the only point in which I had found them to agree, rested upon a fundamental error.  I have since recognized that it is thus in the majority of cases, so that one may almost certainly pronounce erroneous any statement in regard to which all the masters of art agree.