I have gone too far to believe that.

Take man at the very moment of death--have everything ready, do what you will--my artificial heart is a very perfect instrument, mechanically speaking--and how long does it take to start the artificial circulation through the carotid artery?
Not a hundredth part so long a time as drowned people often lie before being brought back, without a pulsation, without a breath.

Yet I never succeeded, though I have made the artificial heart work on a narcotised rabbit, and the rabbit died instantly when I stopped the machine, which proves that it was the machine that kept it alive.
Perhaps if one applied it to a man just before death he might live on indefinitely, grow fat and flourish so long as the glass heart worked.
Where would his soul be then?
In the glass heart, which would have become the seat of life?
Everything, sensible or absurd, which I can put into words makes the soul seem an impossibility--and yet there is something which I cannot put into words, but which proves the soul's existence beyond all doubt.

I wish I could buy somebody's soul and experiment with it." He ceased and sat staring at his specimens, going over in his memory the fruitless experiments of a lifetime.

A loud knocking roused him from his reverie.