No, he is no longer the inmate of Pavilion No.

17, the madman of Healthful House, and I ask myself whether he is not radically cured, whether there is no further danger of his reason collapsing in a final paroxysm.
He has just laid two glass phials upon the table, and holds a third in his hand.

He holds it up to the light, and observes the limpidity of the liquid it contains.
I have half a mind to rush in, seize the tubes and smash them, but I reflect that he would have time to make some more of the stuff.

Better stick to my first plan.
I push the door open and enter.
"Thomas Roch!" I exclaim.
He has not heard, nor has he seen me.
"Thomas Roch!" I repeat.
He raises his head, turns and gazes at me.
"Ah! it is you, Simon Hart!" he replies calmly, even indifferently.
He knows my name.

Engineer Serko must have informed him that it was Simon Hart, and not Keeper Gaydon who was watching over him at Healthful House.
"You know who I am ?" I say.
"Yes, as I know what your object was in undertaking such a position.
You lived in hopes of surprising a secret that they would not pay for at its just value!" Thomas Roch knows everything, and perhaps it is just as well, in view of what I am going to say.
"Well, you did not succeed, Simon Hart, and as far as this is concerned," he added, flourishing the phial, "no one else has succeeded, or ever will succeed." As I conjectured, he has not, then, made known the composition of his deflagrator.
Looking him straight in the face, I reply: "You know who I am, Thomas Roch, but do you know in whose place you are ?" "In my own place!" he cries.
That is what Ker Karraje has permitted him to believe.