The Documents in the Case

to split it into its two asymmetric forms. We can’t do that mechanically. We can do it by the exercise of our living intelligence, of course, by laboriously picking out the crystals. Or we can do it by swallowing the substance, when our bodies will absorb and digest the dextro-rotating form of, for example, glucose, and pass the laevo-rotating form out unchanged. Or we can get a living fungus to do it for us, such as blue mould, which will feed on and destroy the dextro-rotatory half of the racemic form of paratartaric acid and leave unchanged the laevo-rotatory half, which is the artificial, laboratory-made half. But we can’t, by one mechanical laboratory process, turn an inorganic, inactive, symmetric compound into one single, asymmetric, optically active compound⁠—and that is what living matter will do cheerfully, day by day.”

Waters finished his exposition with a smart little thump of the fist on the table. I knew what that was. It was the postman’s knock, bringing the answer to that letter of mine. A horrid sinking feeling at the solar plexus warned me that in a very few minutes I should have to ask a question. Why need I do it? The subject was remote and difficult. I could easily pretend not to understand. If there really was a difference between the synthetic and the natural product, it was not my business to investigate it. Waters was changing the subject. He had gone back to the first day of creation. Hang him! Let him stay there!

“So that, as Professor Japp said, as long ago as 1898, ‘The phenomena of stereo-chemistry support the doctrine of vitalism as revived by the younger physiologists, and point to the existence of a directive force, which enters upon the scene with Life itself and which, in no way violating the laws of the kinetics of atoms’⁠—that ought to comfort you, Hoskyns⁠—‘determines the course of their operation within the living organism. That is that at the moment when Life first arose, a directive force came into play⁠—a force of precisely the same character as that which enables the intelligent operator, by the exercise of his will, to select one crystallised enantiomorph and reject its asymmetric opposite.’ I learnt that passage by heart once, as a safeguard against cocksureness and a gesture of proper humility in face of my subject.”

“In other words,” said Matthews, “you believe in miracles, and something appearing out of nowhere. I am sorry to find you on the side of the angels.”

“It depends what you mean by miracles. I think there is an intelligence behind it all. Else, why anything at all?”

“You have Jeans on your side anyway,” put in Hoskyns. “He says, ‘Everything points with overwhelming force to a definite event, or series of events, of creation at some time or times, not infinitely remote. The universe cannot have originated by chance out of its present ingredients.’ I can’t tell you what produced the first molecules of gas, and you can’t tell me what produced the first asymmetric molecules of Life. The parson here may think he knows.”

“I don’t know,” said Perry, “but I give it a name. I call it God. You don’t know what the aether is, but you give it a name, and deduce its attributes from its behaviour. Why shouldn’t I do likewise? You people are making it all very much easier for me.”

It was no good. I had to ask my question. I burst in, violently, inappropriately, on this theological discussion:

“You mean to tell me,” I said, “that it is possible to differentiate a substance produced synthetically in the laboratory from one produced by living tissue?”

“Certainly,” said Waters, turning to me in some surprise, but apparently accepting my tardy realisation of this truth as mere vagary of my slow and unscientific wits. “So long, of course, as the artificial substance remains in the first or racemic form, for this would be optically inactive, while that from the living tissues would rotate the beam of polarised light, when viewed in the polariscope. If, however, that racemic form had been already split up by the intelligent operator, or some other living agency, into its two dextro- and laevo-rotary forms, it would be impossible to distinguish between them.”

I saw a path of escape opening up. Surely the synthetic muscarine at St. Anthony’s would have had this other operation performed on it. There was no reason at all why I should interfere. I relapsed into silence, and the conversation wandered on.

I was recalled to myself by a movement about me. Matthews was explaining that he had to be getting home. Waters rose to accompany him. In a minute he would be gone and the opportunity lost. I had only to sit still.

I got up. I made my fatuous farewells. I said I had a perfectly good wife to go home to. I thanked my host and said how much I had enjoyed the evening. I followed the other men out into the narrow hall, with its loaded umbrella-stand and ugly, discoloured wallpaper.

“Dr. Waters,” I said.

“Yes?” He turned smiling towards me. I must say something now or he would think me a fool.

“May I have a word with you?”

“By all means. Which way do you go?”

“Bloomsbury,” said I, hoping desperately that he lived at Hendon or Harringay.

“Excellent, I am going that way myself. Shall we share a taxi?”

I murmured something about Professor Matthews.

“No, no,” said he, “I’m going by tube to Earl’s Court.”

We found our taxi and got in.

“Well, now?” said Waters.

I was in for it now. I told him the whole story.

“By God,” he said, “that’s damned interesting. Fine idea for a murder. Of course, any jury in the country would be only too ready to believe it was accident. Tempting Providence, and all that. And unless your man was fool enough to use the synthetic muscarine in its racemic form, you know, I’m very much afraid he’s pulled it off. There’s a chance, of course. They may not have gone further than that. Why