I certainly did. Callahan's name always reminded me of the time I took testimony in Sing Sing Prison on a Callahan application in Interference. But I nodded numbly and went back to my office and finished the bottle of milk of magnesia and caught a cab to the Marchare Laboratory. * * * It was cool in the lab and the air smelled faintly of solvents. I liked the smell, and I sniffed it deeply and tried to distinguish one from the other. My chemistry professor had often told me that I had the best nose he had run across in twenty-five years of teaching. I picked out the pungent, aromatic odor of toluene and the hospital smell of diethyl ether, and I thought I could detect the heavy odor of lauryl alcohol. Underneath them all was a rich, sweet smell that I had smelled before, but I couldn't tell what it was. I decided it was a lactone, and let it go at that. I nodded as I went past the receptionist, and her smile made me feel uncomfortable again, just as it always did; there was too much of a leer in it. I never stopped to tell her where I was going; I just went in unannounced. I went up the stairs and down the hall to Callahan's lab, next to Dr. Marchare's. I went in. Henry Callahan stood at a bench pouring a colorless liquid down a chromatographic column. He looked over at me and said, "Well, Carl Saddle. How are you, man? Nice to see you." Callahan was a big man, heavy-set, with bright blue eyes, and a shock of light-brown hair. For all his bulk he moved lightly as befitted a former stroke on the Penn crew. I was fond of Callahan, even with all the trouble his inventions caused me; I knew he couldn't help it. I said, "Hello Henry. How have you been?" And we exchanged some more amenities. Finally he said, "Carl, we have quite a problem here, and we don't know what to do about it. Here's the situation." I swallowed, and took out my notebook and pencil, and laid my pocket slide rule in front of me. I always put the slide rule out where the inventor can see it to remind him that he is talking to another technical man, not just a lawyer. This helps make him stick to the facts. I didn't need the rule with Callahan, but habit is hard to break. Callahan said, "Some time ago I made a polyester, used adipic acid and an amino alcohol. On a hunch I dropped in an aluminum alkyl, and then pushed the polymerization along with both ultraviolet and heat. Got a stiff gel out of the pot and drew it into a quarter of a pound of fibers. I only had time to determine that the fibers were amorphous--no time to draw them further to see if they would develop crystallinity. I put them in an open-mouth jar which I later found had been used to store mercury. One evening I took them out and found they had developed crystallinity on standing. Furthermore, the fibrous ends had split, and the split ends seemed to be tacky--seemed a natural to me to make a sheet of paper out of it."