Editor's note: We are pleased to present the fourth and final episode of a gothic short story by chemical engineer Mark Keane. Use the navigation links above right to catch up previous parts.

JJuliet was overjoyed with the results of the experiment. Everything now tasted sugary, which was to her liking. Extended tests with different doses of the organometallic complex allowed the Professor to fine-tune his control of the sweet taste receptors in terms of intensity and duration.

Beezie was surprised to see Juliet eat the florets of broccoli she would normally have pushed to one side of her plate or attempted to hide under a napkin. She now wolfed down slices of smoked salmon, once the yuckiest of all food, and asked for more. Each morning began with a huge helping of porridge that was heavily salted. Beezie attempted to broach this unexpected development with the Professor but he would only say he had spoken to Juliet and as a caring father had insisted she alter her diet.

The Professor was sorely tempted to present his successful results to learned colleagues, Prausnitz at the very least. Something held him back. It was still too early. The tests thus far could only be regarded as preliminary. He needed to extend the range of effects. The work must be conducted in a systematic fashion. The next sense to consider was smell. He had already been giving this some thought. Tweaking the olfactory receptors would bring greater insight in controlling nerve impulses to the brain.

The Professor was clear on the direction the research should take. From his reading of the literature, these receptors had limited selectivity and exhibited affinity for a range of odours. His work with Juliet was still very much a question of trial and error, but he now had a better feel for the required dosage.

The initial trials were rudimentary and crude. Juliet was wholehearted in her cooperation, such was her enthusiasm following her experience of sugary salt. Her eagerness soon waned after repeated exposure to the vials of sulphurous thiol and mercaptan with their bouquet of garlic, urine and faecal matter.

The Professor prevailed with promises of sweet-scented roses and magnolias, candy and cinnamon. He endured her shrieks of pooey poo, yucky and poopy. He suppressed the urge to grab her neck and squeeze until she no longer complained.

The Professor persevered. He dabbed a handkerchief against his glistening brow and ignored her whining as he held her head steady. He wafted a sequence of vials beneath her scrunched-up nose. At last he met with some measure of success. He did not feel the pressure of her head against his restraining palm when he introduced the foul mercaptan. She had not reacted to the vapours. Her face was impassive. He took a whiff and recoiled in disgust. A definite result. Excellent, the tridentate ligand in the complex he administered had acted to poison the olfactory receptor sites.

He was struck by an idea. He grabbed Juliet’s wrist and dragged her down to the basement where Beezie had her rooms. It was Sunday, approaching two o’clock. Beezie used the Day of the Lord to minister to her particular needs. Church in the morning followed by prearranged visits to an assortment of relatives. She served the Professor and Juliet their light lunch and then retired to her quarters to gorge on her own Sunday speciality of boiled cabbage, parsnips and bacon which she drowned in horseradish sauce. The Professor had occasion in the past to visit the kitchen on a Sunday and had witnessed her preparation of this vile repast.

His timing was perfect as Beezie was just leaving the downstairs toilet when they reached the foot of the stairs. He waited until she had returned to her bedroom and closed the door. He pushed Juliet towards the toilet. With the bile rising from his stomach and gagging uncontrollably, he shut her inside.

He counted to twenty, his back against the door with his wife's scarf used before as blindfold now covering his mouth and nose. Beezie’s dense, rank and corrosive gasses penetrated this cover and attacked his olfactory receptors, causing his stomach to heave involuntarily. He opened the door and frogmarched Juliet upstairs away from the putrid cesspit. When they reached his study the Professor removed the scarf and stood before an open window gulping fresh air to expel Beezie's rancid redolence.

He turned his attention to Juliet, who appeared quite concerned. What did you experience in that hellish water closet, what did you smell? Nothing. Juliet’s answer was simple and unequivocal. This was indisputable proof. A most singular quod erat demonstrandum – but not one he could write up and submit to any respectable scientific journal. One moreover that he could not present before the eminent gentlemen of the Royal Academy. Immunity to the insidious aroma of Beezie's faecal emissions would not impress the staid scientific establishment.

Further tests, however, did not take him beyond this point. He produced a range of formulations at the requisite concentration to inhibit the olfactory receptors and allow Juliet enjoy all manner of noxious smells without batting an eyelid. But he was unable to selectively activate receptors and induce sensitivity to an individual odour in the test mixtures. Musk and ammonia, vanilla and hydrogen sulphide were equivalent to his young assistant. Some of his prototype solutions had no effect and Juliet would grimace, kick out and wriggle from his grip.

In vain did he seek the transformation of feculence to cologne. This would have to remain an elusive Holy Grail for now. One evening his hopes were raised when Juliet claimed she could detect a hint of marzipan as he opened the container of butanethiol. These were dashed when he realised the suggestion of almonds was the result of residual vapours from the aldehydes he had been working with in the laboratory that day.

The Professor accepted that he must move on from his tinkering with odours that had delivered only marginal success. He had tired of the incessant stink of thiols. Juliet was showing signs of resistance, sighing and shrugging belligerently whenever he approached her with his box of smells. There was a danger of receiving erroneous results from his contrary collaborator. He had to keep the fickle creature on his side. Surely Faraday or Cavendish were never faced with these difficulties.

He must try something that was less taxing on his juvenile assistant. He would tackle the sense of vision and see if he could tweak the photoreceptors. He already had identified a family of complexes that should act as filters so that one colour predominated. He put this to Juliet, vaguely uneasy that the suggestion would conjure up some association with Carass. She agreed to his proposal without hesitation. The frivolous child had clearly forgotten the goldfish. It was galling that he had to receive her endorsement before he proceeded with his research.

The next set of tests went smoothly. He held up a card of the most vivid azure, a clear sky on a magnificent sunny day. What colour do you see. Red. A distinctive green frog was coloured navy. A cartoon yellow sun presented a crimson face. The flag of Romania became the flag of Guinea. He had successfully manipulated the cone cells in Juliet’s retina. The girl was happy to live for extended periods in a world of monochrome blue or yellow.

Further experiments with the sense of touch produced immediate results. If anything they worked too well. It was impossible to restrain Juliet from exploring the unexpected responses to her probing fingers. The Professor tried to educate her on the complexity of the somatosensory system. She was only interested in the amazing changes to her tactile perception. Ice cubes now felt hot to the touch. She reached out in wonder for the most banal items as though she had returned to the early years of her short life, prostrate in her pram and instinctively stretching for dangling solid shapes. The Professor’s desk felt rough to Juliet’s tentative exploration with bumps, undulations and sharp points that she could feel but not see. When asked to describe the texture of the curtain fabric she described the pebble-dash finish on the external walls of the house. She spent prolonged periods caressing the sisal front-door mat in wonderment at its satin smoothness.

The Professor should have foreseen that this misplaced fervour would lead to problems. It came to a head when Beezie saw Juliet staggering about the kitchen, her motor control failing her, both cheeks stripped of skin and dripping blood. When asked what had happened, she held up a bloody cheese grater and mumbled something incoherent about its warm furriness. She had rubbed it against her face as though it was the soft coat of a sleek feline.

Juliet was taken to hospital. The concerned Professor stuck to her side. It was impossible to disguise his anxiety at the prospect of searching questions regarding the cause of the girl’s injuries. He could not rely on her discretion. Circumspection was not one of Juliet’s attributes. Fortunately the medical staff were harried and did not have time to examine her case too deeply. They washed, disinfected and bandaged her wounds. She was detained overnight. The Professor left the hospital long after standard visiting hours. He returned first thing in the morning to take her home. This had been a warning. He must be more vigilant.

What next? It was time to move on from parlour games and strive for something more ambitious, something truly extraordinary. Enough of the flim-flam. He was no confidence trickster, his work was ground-breaking.

But nobody was interested in the elegance of metal-ligand coordination or in the complications inherent in compound synthesis. The fine balance of interrelated parameters that can generate a multitude of permutations was now under his control. He had enough material for dozens of journal articles that would be pored over by maladjusted and spiteful academics from Berlin to Beijing. Work that would be dissected, ruthlessly copied, discounted and forgotten. A demonstration of the power of his formulations was required that would make academics and non-academics sit up and take notice.

Inhibiting malodours, sweetening the sour and roughening the smooth were inconsequential. Control and adjustment of emotions should now be his target. Even a sharpening of the intellect. A formulation to convert the depressive into an optimist, the anxious into the confident, the dullard into the innovative. This was the natural extension of his work to preferentially activate or deactivate sensors and receptors. Manipulation of neurons, hijacking and redirection of information to the brain. What was the nervous system if not a sequence of chemical pathways? He was merely lending a helping hand to direct reactions towards a particular product or effect.

The Professor knew he was now considering well-trodden and grubby furrows in research. He scorned the mercenary world, cared nothing for commercial possibilities in drug production and was repelled by the seedy business of research funding. His aversion was deep-seated for those who knew only research proposals and budgets. He did not envy his funded colleagues their pots of money or the bogus applause this brought them. His interest had never extended beyond the complexities of inorganic chemistry and the manipulation of ligands and chelates to his will. Now he had reached the point of moving his research from flask and reactor into the human mind. If his work brought awards and the grudging respect of his bitter academic competitors so much the better. Why should he not enjoy acclaim and accept accolades that were by right his?

The Professor must now be cautious in his approach and tiptoe gingerly forward. Don the velvet glove and eschew the jack-boot. He would first tackle a system with some precedent and consider the feasibility of using his complexes to release dopamine. The neurotransmitter was well-established to induce a sense of well-being and elation. More importantly, additional dopamine increased alertness, brain-power, retention and comprehension. If he could tailor the amount of dopamine released to produce moderate effects, a mild bliss, there should be no highs or risk of addiction. The ultimate goal was to facilitate delight with insight. From the outset this was where his research had always been heading with Juliet as his aide.

He worked with renewed intensity in the laboratory on a sequence of tricky multi-stepped syntheses. He laboured alone and was oblivious to the lethargy of his students, impassive in the face of the petty subversions of his colleagues. After many weeks he arrived at three formulations that warranted testing. The first produced no effect. Juliet cooperated fully but there was a tenseness in the study. Even she must have been aware that his work had taken on a greater sense of urgency. He was aggressively offhand when she innocently enquired about the expected results. She did not seem overly bothered by this as he had never told her what she should experience. Her father administered the second solution in silence. There was no detectable response. He applied the third chemical a little too hastily, as the two failures had been so disappointing. Juliet displayed absolutely no sign of the anticipated alertness or euphoria.

He sat in his study working through chemical pathways and mechanisms that he drew out on loose sheets of paper. At least one of the compounds should have yielded results. He was pondering the prudence of increasing the dosage strength when his attention was drawn by shrieks and crashing from the downstairs kitchen.

He was met by a chaotic scene, the crunch of broken crockery underfoot, Juliet's piercing screams as she flung plate after plate at the cowering Beezie. He had to grip both her arms to restrain her but this only increased the pitch of her squeals. She struggled against his hold and he was amazed by the strength her thin body possessed as she wriggled fiercely. She kicked his shins and spat in his face. His shock caused him to balk and he hit out impulsively, a heavy slap that knocked her to the ground. He was fenced in by internal and external bedlam. The wailing child was crumpled beneath him, her hands and knees cut by the sharp shards of broken plates and cups. Beezie was sobbing at the table.

The Professor turned and was stunned to see Prausnitz standing in the doorway. His friend took matters in hand and moved immediately to pacify Beezie. She helped him take Juliet to her room and settle her in bed. The housekeeper endeavoured to placate the child with reassuring cooing sounds and caresses.

Prausnitz evinced avuncular calm. The two academics worked together to right the kitchen, sweeping up debris and rearranging the chairs that had been flung about the room. The Professor was more reserved than usual. He made a disjointed attempt to excuse Juliet’s behaviour but Prausnitz waved away his words. Beezie reappeared to let them know that Juliet was asleep. The Professor placed a hand on the housekeeper’s elbow and stressed that they should do nothing to upset her. Later the girl suffered severe nausea that brought on wretched vomiting fits. In truth Beezie enjoyed her role as nurse and Juliet responded to her ministration. Her illness passed. The Professor discontinued his tests.

The Professor was found one morning in May slumped over his desk. The curtains were drawn in the study. He had a pen in his right hand. The entries in his notebook ended in an indecipherable scrawl and jagged line. The doctor who was called in estimated that he had been dead for ten hours or so, a suspected fatal heart attack. The Professor had been pushing himself too hard the previous weeks, if not at the university then closeted in his study for hours on end. There was a history of heart disease in the family, Beezie claimed with gratuitous glee.

Naturally Juliet was severely affected by his death. The few relatives who attended the funeral nodded solemnly in commenting on the reverence with which she had held her father. Juliet was withdrawn and did not speak a word. The child was suffering from shock. Her silence leant an air of gravitas to her mourning. She was still very young and would no doubt soon recover. In contrast, her two strapping brothers behaved far too boisterously at the funeral ceremony, seemingly unconcerned by the death of their father. Prausnitz was present but remained in the background. He monitored proceedings, Juliet in particular. He had his suspicions but his sardonic mask gave little away.

All Juliet had wanted was to help her father. He had seemed so forlorn and distressed seated at his desk, his head supported by two clenched fists. When she asked him why he was so sad he sighed. He was not as accomplished as he had believed himself to be. He was in need of inspiration. His research had reached a dead end. The latest compounds had not generated positive results in covert animal trials. He could not decide his next step.

Juliet was distressed to see her father so helpless. She had only added a few drops of the solution to the glass of brandy he took each evening at six o'clock. Only a few drops. She was not to know the solution was very concentrated and had been purified and re-purified. Or that the experimental formulation had proved fatally toxic in tests on laboratory mice. All Juliet wished was to support her father in his valuable work. He had told her she had been of enormous assistance before. Her contribution had given him such belief that his research would reach the greatest conceivable heights.

It is of course possible that in his final hours or minutes or even seconds, the Professor experienced feelings of benevolence, gratification and beneficence as his unique organometallic complex took hold. He may even have attained greater insight with a final ice-sharp penetration. This would have pleased him. How fitting if it resulted in a sense of fulfilment as he experienced first-hand his success at experimenting with the senses.