Whether it was a question of history or of cosmogony, or whether he was handling a test-tube or a blow-pipe; what he was about I did not feel sure; but I took it for granted that it was some crucial question or other he was at work on, some point bearing on the thought of the time. For the Master, I have observed, is pretty sagacious in striking for the points where his work will be like to tell. We all know that class of scientific laborers to whom all facts are alike nourishing mental food, and who seem to exercise no choice whatever, provided only they can get hold of these same indiscriminate facts in quantity sufficient. They browse on them, as the animal to which they would not like to be compared browses on his thistles. But the Master knows the movement of the age he belongs to; and if he seems to be busy with what looks like a small piece of trivial experimenting, one may feel pretty sure that he knows what he is about, and that his minute operations are looking to a result that will help him towards attaining his great end in life,--an insight, so far as his faculties and opportunities will allow, into that order of things which he believes he can study with some prospect of taking in its significance. I became so anxious to know what particular matter he was busy with, that I had to call upon him to satisfy my curiosity. It was with a little trepidation that I knocked at his door. I felt a good deal as one might have felt on disturbing an alchemist at his work, at the very moment, it might be, when he was about to make projection. --Come in!--said the Master in his grave, massive tones. I passed through the library with him into a little room evidently devoted to his experiments. --You have come just at the right moment,--he said.--Your eyes are better than mine. I have been looking at this flask, and I should like to have you look at it. It was a small matrass, as one of the elder chemists would have called it, containing a fluid, and hermetically sealed. He held it up at the window; perhaps you remember the physician holding a flask to the light in Gerard Douw's “Femme hydropique”; I thought of that fine figure as I looked at him. Look!--said he,--is it clear or cloudy? --You need not ask me that,--I answered. It is very plainly turbid. I should think that some sediment had been shaken up in it. What is it, Elixir Vitae or Aurum potabile? --Something that means more than alchemy ever did! Boiled just three hours, and as clear as a bell until within the last few days; since then has been clouding up. --I began to form a pretty shrewd guess at the meaning of all this, and to think I knew very nearly what was coming next. I was right in my conjecture. The Master broke off the sealed end of his little flask, took out a small portion of the fluid on a glass rod, and placed it on a slip of glass in the usual way for a microscopic examination.