The Girl with All the Gifts

50

The fourth day is the day of the miracle, which falls on Caroline Caldwell out of a clear sky.

Except that it’s not clear, really. Not any more. The weather has turned. A thin rain is soaking through their clothes, there’s no food left, and everyone is in a dismal, surly mood. Parks is worried about the e-blocker, and taking it out on everybody. They’re running low on the stuff, and had to go sparingly when they anointed themselves before unlocking the door. And they’ve still got at least three days’ journey ahead of them. If they don’t manage to restock at some point, they’ll be in dead trouble.

They’re still walking south, with the whole of north London and central London and south London to get through. Even for the young private, Caldwell sees, some of the shock and awe has drained away. The only one who’s still looking at every new thing they pass with indefatigable wonder is test subject number one.

As for Caldwell, she’s thinking about lots of things. Fungal mycelia growing in a substrate of mammalian body cells. The GABA-A receptor in the human brain, whose widespread and vital operation concerns the selective conduction of chloride ions across the plasma membranes of specific neurons. And the more immediate issue of why they’re seeing so few hungries now, when yesterday morning they were seeing clusters of several hundred at a time.

Caldwell hypothesises a number of possible answers to this question: deliberate clearance by uninfected humans, competition from an animal species, the spread of a disease through the hungry population, an unknown side effect of Ophiocordyceps itself, and so on. Obviously the existence of the fallen, fruiting hungries is a factor – they’ve seen a lot more since they set out that morning, so many that new sightings arouse no comment – but it’s unlikely that this is the sole explanation. For that, there would have to be hundreds of thousands of the things, not just dozens. To Caldwell’s intense annoyance, she comes across no observational evidence that would help her to choose between the various scenarios she’s theorised.

Moreover – and this distresses her even more – she’s finding it hard to concentrate. The pain from her damaged hands is now a persistent and agonising throbbing, as though she had an extra heart beating in each of her palms in very imperfect synchrony. The ache in her head tries to keep pace with both at once. Her legs feel so weak, so insubstantial, she can hardly believe that they’re carrying her weight. It’s more like her body is a helium balloon, bobbing along above them.

Helen Justineau says something to her, the rising inflection suggesting a question. Caldwell doesn’t hear, but nods her head in order to prevent any further repetition.

Perhaps Ophiocordyceps induces different behaviours in the mature stage than in its neotenous, asexual form. Migratory behaviours or sessile ones. Morbid photosensitivity or some parallel to the height-seeking reflex of infected ants. If she knew where the hungries had gone, she could begin to construct a model of the mechanism, and that might lead her to an understanding of how the fungus–neuron interface ultimately functions.

The day has a drifting, dreamlike feel. It seems to come to Caldwell from a great distance, only reporting in occasionally. They find a cluster of fallen hungries, who have fruited in the same way as the others – but in this case, they’ve lain down so close together that the trunks or stems that grow out of their chests are now joined together by rafts of mycelial threads.

While the others stare at the fungal glade in sick fascination, Caldwell kneels and picks up one of the fallen sporangia. It looks and feels solid enough, but weighs very little. There’s a pleasing smoothness to its integument. Nobody sees as she slips it, very carefully, into the pocket of her lab coat. The next time Sergeant Parks glances around at her, she’s fidgeting with her bandages again and looks as though she’s been doing it the whole time.

They walk on endlessly. Time elongates, fractures, rewinds and replays in stuttering moments that – while they have no coherent internal logic – all seem drearily familiar and inevitable.

The GABA-A receptor. The hyperpolarisation of the nerve cell, occurring after the peak of its firing and determining the lag time before it’s ready to reach action potential again. So precariously balanced a mechanism, and yet so much depends on it!

“Approach with caution,” Sergeant Parks is saying now. “Don’t assume it’s empty.”

In her lab at the base, Caldwell has a voltage clamp of the SEVC-d variety, which can be used to measure very small changes in ion currents across the surface membranes of living nerve cells. She never trained herself to use it properly, but she knows that the Cordyceps-infected display both different levels of excitation from healthy subjects and different rates of change in electrical activity. Variation within the infected community is large, though, and unpredictable. Now she’s wondering whether it correlates with another variable that she’s failed to detect.

A hand touches her shoulder. “Not yet, Caroline,” Helen Justineau says. “They’re still checking it out.”

Caldwell looks on down the road. Sees what’s standing there, a hundred yards ahead of them.

She’s afraid at first that she might be hallucinating. She knows she’s suffering from extreme fatigue and mild disorientation, arising either from the infection contracted when she injured her hands at the base or (less likely) from the untreated water they’ve been drinking.

Ignoring Justineau, she walks forward. In any case, the sergeant rounds the side of the thing now, and gives the all-clear. There’s no reason to hang back.

She raises her hand and touches the cool metal. In curlicues of raised chrome, from under its mantle of dust and filth, it speaks to her. Speaks its name.

Which is Rosalind. Rosalind Franklin.