It is a long time since I last knew sleep. I dare not let myself drink of the waters of Lethe; for, if I do, I shall dream. And, if I dream, they shall find me.

Can it only be a month ago that I volunteered to help my tutor, Professor J_, in his studies into the nature of perception? He had devised a means of stimulating those centres of the brain responsible for interpreting the senses. His apparatus consisted of a cap containing induction coils that had been connected to a current generator. In his experiments, Professor J_ had already shown that it was possible by careful application of specific currents to generate sensory distortions. These distortions were crude and simple, restricted to changes in colour or the generation of audible tones.

Professor J_ had theorised that the sensations generated by his apparatus were not sufficient to convince the conscious mind. After all, it was already engaged with the information gathered from the body's natural senses. However, if the artificial stimuli were to be induced in a brain that was receptive but not aware of any other sensory input - say, the brain of a sleeper? - then perhaps the brain would be more responsive?

So, to prove his theory, Professor J_ devised a series of experiments. A group of volunteers would be given a sleeping draught, then connected to the professor's apparatus. The professor would then try to generate dreams in his subjects who, on awakening, would report what they had experienced during the night.

Naturally I and the other students in Professor J_'s classes volunteered to participate. For a month before the experiments proper, the professor subjected us to the effects of his device, recording and analysing our conscious responses. Then, when he was sure that he had gathered sufficient knowledge of the workings of our minds, the study began. For a week, I and my fellows lay in dormitory beds, under the influence of Professor J_'s machine. Each morning, immediately after we woke, we would record our dreams and present our notes for analysis.

After a few nights, some of the volunteers reported strange dreams in which they claimed to be in another body. The professor was delighted. At last - here was some evidence that might support his claims! Then, one night, a volunteer reported that he had dreamt of a world inhabited by creatures resembling jellyfish composed of luminous gases. The volunteer had attempted to touch one of these creatures, but on doing so it had exploded in a flash of colours. As the experiment progressed, more and more of the volunteers reported similar dreams. Professor J_ was even more pleased with this development. Now that he was achieving consistent results, he could refine his experiment.

All seemed to be going well until, one night, we were woken by a hideous scream from one of the dormitories. Shaking off the last remnants of sleep, we hurried to see what had happened. One of the volunteers, a sensitive youth by the name of A_ M_, was dead! The college doctor examined M_'s corpse, then pronounced his verdict: M_ had died of a congenital weakness in the sinuses of his brain. The weakness had given way as he slept, resulting in his untimely demise.

Professor J_ was grief-stricken. While the blame for M_'s death could not be laid firmly at his feet, the professor still felt responsible for what had happened. After all, M_ had been one of his volunteers. Professor J_ decided that it would be best, if only for a while, to cease his investigations. Another death would be an indelible stain upon his conscience.

Unfortunately for the professor, the deaths did not stop. The next night, another one of Professor J_'s students died - and then another! The cause of the deaths was exactly the same as that of M_. The remaining volunteers met to compare notes. To our astonishment, despite the cessation of the experiment, we were all still experiencing the same dreams of luminous beings. However, it seemed to us that the beings were more aggressive than before. In addition, those who had been in the same rooms as M_ and the other unfortunates reported that they had seen clusters of the luminous beings in their dreams, and that these clusters had faded away just before the deaths of their friends.

As time passed, more and more of our number fell to the mysterious malady. What was causing this? What could we do? We did not know. All we knew was that each night we would fall asleep and, come the morning, there would be one less of us. We became like condemned men, waiting for their turn on the scaffold.

One night, in my dreams, the luminous beings surrounded me. They advanced towards me, their glowing tentacles outstretched before them, their forms a baleful crimson. To my shame, I have to say that my fear overtook me and I cried out in terror. I woke screaming - but alive! One of my friends was not so fortunate, however.

I pondered what had happened. These beings only attacked us in our dreams, but could not harm us if we were awake. If that was the case, then all we had to do was not to dream! But that could only be achieved if we did not fall asleep. I informed the others of this. Some believed me; some did not. By the next morning, another of our number had died: one who had slept. My theory had been proven true.

We resolved to stay awake. We watched each other, keeping our companions from falling asleep. We took stimulants to give us the necessary energy. Those who could not or would not ultimately fell asleep and never woke again.

It it so long since I last slept. I dare not. I keep myself awake with drugs; otherwise my body will betray me. But they have taken their toll. I have started to hallucinate, to experience what could be described as waking dreams. The luminous beings seem to follow me, watching me from just beyond my field of vision. Soon I will be unable to distinguish dreams from reality, and then I must face my fate.