The Faber Book of Science

by John Carey

  The afternoon was very hot and overcast and I remember opening the diaphragm of the substage condenser of the microscope to admit more light and then changing the focus. In each of these cells there was a cluster of small granules, black as jet and exactly like the black pigment granules of the plasmodium crescents [the crescent-shaped form of the malaria parasite]. As with that pigment, the granules numbered about 12 to 16 in each cell and became blacker and more visible when more light was admitted through the diaphragm. I laughed and shouted for the hospital assistant – he was away having his siesta …

  Next day I went to hospital intensely excited. The last survivor of the batch fed on the 16th, mosquito 39, was alive. After looking through yesterday’s specimen I slew and dissected it with a shaking hand. There were the cells again‚ 21 of them, just as before, only now much larger! Mosquito 38, the seventh of the batch fed on the 16th, was killed on the fourth day afterwards – that is, on the 20th. This one was killed on the 21st, the fifth day after feeding, and the cells had grown during the extra day. The cells were therefore parasites and, as they contained the characteristic malarial pigment, were almost certainly the malaria parasites growing in the mosquito’s tissues.

  The thing was really done. We had to discover two unknown quantities simultaneously – the kind of mosquito which carries the parasite and the form and position of the parasite within it. We could not find the first without knowing the second nor the third without knowing the first. By an extremely lucky observation I had now discovered both the unknown quantities at the same moment. The mosquito was the anopheles and the parasite lives in or on its gastric wall and can be recognized at once by the characteristic pigment. All the work on the subject which has been done since then by me and others during the last 25 years has been mere child’s play which anyone could do after the clue was once obtained.

  That evening I wrote to my wife: ‘I have seen something very promising indeed in my new mosquitoes,’ and I scribbled the following unfinished verses in one of my In Exile notebooks in pencil:

  This day designing God

  Hath put into my hand

  A wondrous thing. And God

  Be praised. At His command,

  I have found thy secret deeds

  Oh million-murdering Death.

  I know that this little thing

  A million men will save –

  Oh death where is thy sting?

  Thy victory oh grave?

  On the 22nd I wrote to my wife, after mentioning the poem again: ‘I really think I have done the mosquito theory at last, having found something in mosquitoes fed on malaria patients exactly like the malaria parasite.’ Then, or a few days later, I wrote the following amended verses on a separate slip of paper:

  This day relenting God

  Hath placed within my hand

  A wondrous thing; and God

  Be praised. At His command,

  Seeking His secret deeds

  With tears and toiling breath,

  I find thy cunning seeds,

  O million-murdering Death.

  I know this little thing

  A myriad men will save.

  O Death, where is thy sting?

  Thy victory, O Grave?

  About the same time the two subsequent sonnetelles of In Exile were added – also on separate slips for tentative arrangements; and I did not like to change them further when they were published 13 years later. The three final sonnetelles of In Exile had been written previously and the poem was now finished, though I did not know it then.

  Ross’s optimism was premature, though it seemed justified for a time. With the introduction of modern insecticides, notably DDT, at the end of the Second World War, malarial mosquitoes were almost wiped out in many parts of the world. But genes giving resistance to insecticides spread through the mosquito population, and malaria is a major killer disease once more.

  Source: Ronald Ross, Memoirs, London, John Murray, 1923.

  The Poet and the Scientist

  Hugh MacDiarmid is the pseudonym of the poet Christopher Murray Grieve (1892–1978), founder of the National Party of Scotland. His poem ‘Two Scottish Boys’, with its four epigraphs, argues that poets need to be more like scientists. The two ‘boys’ he compares are the Celtic twilight poet William Sharp (1855–1905), who wrote under the pseudonym ‘Fiona Macleod’, and the physician and tropical medicine expert Sir Patrick Manson (1844–1922), nicknamed ‘Mosquito Manson’, who (see p. 204) first suggested to Ronald Ross that the mosquito was host to the malaria parasite. ‘Bunyan’s quag’ (line 4) is the Slough of Despond in The Pilgrim’s Progress; Sainte-Beuve (line 21) was a nineteenth-century French critic, and the French quotation is from an essay he published in 1857 about Flaubert’s novel Madame Bovary.

  Two Scottish Boys

  Not only was Thebes built by the music of an Orpheus, but without the music of some inspired Orpheus was no city ever built, no work that man glories in ever done.

  Thomas Carlyle

  For the very essence of poetry is truth, and as soon as a word’s not true it’s not poetry, though it may wear the cast clothes of it.

  George MacDonald

  Poetry never goes back on you. Learn as many pieces as you can. Go over them again and again till the words come of themselves, and then you have a joy forever which cannot be stolen or broken or lost. This is much better than diamond rings on every finger… The thing you cannot get a pigeon-hole for is the finger-point showing the way to discovery.

  Sir Patrick Manson

  Science is the Differential Calculus of the mind. Art the Integral Calculus; they may be beautiful when apart, but are greatest only when combined.

  Sir Ronald Ross

  There were two Scottish boys, one roamed seashore and hill

  Drunk with the beauty of many a lovely scene,

  And finally lost in nature’s glory as in a fog,

  Tossing him into chaos, like Bunyan’s quag in the Valley of the Shadow.

  The other having shot a lean and ferocious cat

  On his father’s farm, was profoundly interested

  In a tapeworm he found when he investigated

  Its internal machinery in the seclusion of his attic room,

  – A ‘prologue to the omen coming on’!

  For while the first yielded nothing but high-falutin nonsense,

  Spiritual masturbation of the worst description,

  From the second down the crowded years I saw

  Heroism, power for and practice of illimitable good emerge,

  Great practical imagination and God-like thoroughness,

  And mighty works of knowledge, tireless labours,

  Consummate skill, high magnanimity, and undying Fame,

  A great campaign against unbroken servility,

  Ceaseless mediocrity and traditional immobility,

  To the end that European reason may sink back no more

  Into the immemorial embraces of the supernatural …

  Sainte-Beuve was right – the qualities we most need

  (Most of all in sentimental Scotland) are indeed

  ‘Science, esprit d’observation, maturité, force,

  Un peu de dureté,’ and poets who, like Gustave Flaubert,

  (That son and brother of distinguished doctors) wield

  Their pens as these their scalpels, and that their work

  Should everywhere remind us of anatomists and physiologists.

  Poet and therefore scientist the latter, while the former,

  No scientist, was needs a worthless poet too.

  Source: The Complete Poems of Hugh MacDiarmid 1920–76, London, Martin Brian & O’Keeffe, 1978.

  Wasps, Moths and Fossils

  The son of semi-literate peasant farmers in France’s Massif Central, Jean-Henri Fabre (1823–1915) spent his early years on his grandparents’ remote small-holding, since his parents could not afford to feed him. Starting his education at the village primary school, run by the local barber, he won
a bursary to secondary school in Avignon, and became a schoolmaster in Ajaccio, Corsica, where he began to study plants and insects. He was almost entirely self-taught, receiving his only natural history lesson from a biologist who happened to be visiting Corsica and showed him how to dissect a snail.

  Back in Avignon, teaching in the grammar school, Fabre made expeditions into the surrounding countryside and would sit motionless for hours watching insects, to the puzzlement of the yokels, who took him for a half-wit. When he was almost 50 years old he gave up schoolmastering and retired to the small village of Sérignan, near Orange. Here in his ‘hermit’s retreat’, living on fruits, vegetables, and a little wine, he observed insects on a tract of stony ground in front of his house, and also in the surrounding plain, with its scrub of wild thyme and lavender, and on the slopes of Mont Ventoux.

  His accounts of the creatures he studied – wasps, bees, dung beetles, gnats, spiders, scorpions – grew into the ten-volume Souvenirs entomologiques. Picturesque and informal, and enlivened by allusions to his eight children, the family dog, and other minor characters, these essays established Fabre’s greatness as both poet and scientist. To Victor Hugo he was ‘the insect’s Homer’; to Charles Darwin, an ‘incomparable observer’. A strain of callousness, even cruelty, in his writing, accentuated by his tendency to describe his insects as if they were people, and contrasting curiously with his humour and charm, enhances its dramatic quality.

  A turning point in Fabre’s life came when he read a monograph on parasitic wasps by Léon Dufour, which noted how a species of burrowing wasp (Cerceris bupresticida)‚ common in the Landes, placed the bodies of a particular kind of beetle (Buprestis bifasciata) in its burrow for its grubs to feed on when they hatched out. Dufour could not make out why the dead beetles did not decay before the wasp-eggs hatched, and he assumed that the mother wasp must inject them with a preservative. The Sérignan region with its sandy soil was favourable for observing burrowing wasps, and Fabre first directed his attention to a species (Cerceris major) closely related to Dufour’s, which preyed on large weevils. He found that the weevils left in the wasp’s burrow as food were not dead, but paralysed by the mother wasp, which stung them with great accuracy in their thoracic ganglia, and was thus able to leave living food for her grubs. Pricking weevils in the same spot with a fine steel pen dipped in ammonia, Fabre found that he, like the wasp, could induce instant paralysis. Later experiments on other paralysed wasp-victims revealed that they were not only alive but conscious enough to eat, taking drops of sugar solution from the end of a straw.

  In the first of the pieces that follow Fabre investigates the food-arrangements of a third species of burrowing wasp, the yellow-winged Sphex (Sphex flavipennis), which preys on crickets. The second piece shows him in less gruesome mood, surprised by moths. In the third, his imagination works on the least promising material, stone.

  Wasps

  There can be no doubt that the Sphex uses her greatest skill when immolating a cricket; it is therefore very important to explain the method by which the victim is sacrificed. Taught by my numerous attempts to observe the war tactics of the Cerceris, I immediately used on the Sphex the plan already successful with the former, i.e. taking away the prey and replacing it by a living specimen. This exchange is all the easier because the Sphex leaves her victim while she goes down her burrow, and the audacious tameness, which actually allows her to take from your fingertips, or even off your hand, the cricket stolen from her and now offered, conduces most happily to a successful result of the experiment by allowing the details of the drama to be closely observed.

  It is easy enough to find living crickets; one has only to lift the first stone, and you find them, crouched and sheltering from the sun. These are the young ones of the current year, with only rudimentary wings, and which, not having the industry of the perfect insect, do not yet know how to dig deep retreats where they would be beyond the investigations of the Sphex. In a few moments I find as many crickets as I could wish, and all my preparations are made. I establish myself on the flat ground in the midst of the Sphex colony and wait.

  A huntress comes, conveys her cricket to the mouth of her hole and goes down alone. The cricket is speedily replaced by one of mine, but placed at some distance from the hole. The Sphex returns, looks round, and hurries to seize her too distant prey. I am all attention. Nothing on earth would induce me to give up my part in the drama which I am about to witness. The frightened cricket springs away. The Sphex follows closely, reaches it, darts upon it. Then there is a struggle in the dust when sometimes conqueror, sometimes conquered is uppermost or undermost. Success, equal for a moment, finally crowns the aggressor. In spite of vigorous kicks, in spite of bites from its pincer-like jaws, the cricket is felled and stretched on its back.

  The murderess soon makes her arrangements. She places herself body to body with her adversary, but in a reverse position, seizes one of the bands at the end of the cricket’s abdomen and masters with her forefeet the convulsive efforts of its great hind-thighs. At the same moment her intermediate feet squeeze the panting sides of the vanquished cricket, and her hind ones press like two levers on its face, causing the articulation of the neck to gape open. The Sphex then curves her abdomen vertically, so as to offer a convex surface impossible for the mandibles of the cricket to seize, and one beholds, not without emotion, the poisoned lancet plunge once into the victim’s neck, next into the jointing of the two front segments of the thorax, and then again towards the abdomen. In less time than it takes to tell, the murder is committed, and the Sphex, after setting her disordered toilette to rights, prepares to carry off her victim, its limbs still quivering in the death-throes. Let us reflect a moment on the admirable tactics of which I have given a faint sketch. The prey is armed with redoubtable mandibles, capable of disembowelling the aggressor if they can seize her, and a pair of strong feet, actual clubs, furnished with a double row of sharp spines, which can be used alternatively to enable the cricket to bound far away from an enemy or to overturn one by brutal kicks. Accordingly, note what precautions on the part of the Sphex before using her dart. The victim, lying on its back, cannot escape by using its hind levers, for want of anything to spring from, as of course it would were it attacked in its normal position. Its spiny legs, mastered by the fore-feet of the Sphex, cannot be used as offensive weapons, and its mandibles, held at a distance by the wasp’s hind-feet, open threateningly but can seize nothing. But it is not enough for the Sphex to render it impossible for her victim to hurt her: she must hold it so firmly garrotted that no movement can turn the sting from the points where the drop of poison must be instilled, and probably it is in order to hinder any motion of the abdomen that one of the end segments is grasped. If a fertile imagination had had free play to invent a plan of attack it could not have devised anything better, and it is questionable whether the athletes of the classic palestra [wrestling-ground] when grappling an adversary would have assumed attitudes more scientifically calculated.

  I have just said that the dart is plunged several times into the victim’s body, once under the neck, then behind the prothorax, lastly near the top of the abdomen. It is in this triple blow that the infallibility, the infused science of instinct, appear in all their magnificence. First let us recall the chief conclusions to which the preceding study of the Cerceris have led us. The victims of Hymenoptera [the group of insects to which wasps belong] whose larva live on prey are not corpses, in spite of entire immobility. There is merely total or partial paralysis, and more or less annihilation of animal life, but vegetative life – that of the nutritive organs – lasts a long while yet, and preserves from decomposition the prey which the larvæ are not to devour for a considerable time. To produce this paralysis the predatory Hymenoptera use just those methods which the advanced science of our day might suggest to the experimental physiologist – namely, wounding, by means of a poisoned dart, those nervous centres which animate the organs of locomotion. We know too that the various centres o
r ganglia of the nervous chain in articulate animals act to a certain degree independently, so that injury to one only causes, at all events immediately, paralysis of the corresponding segment, and this in proportion as the ganglia are more widely separated and distant from each other. If, on the contrary, they are soldered together, injury to the common centre causes paralysis of all the segments where its ramifications spread. This is the case with Buprestids and Weevils, which the Cerceris paralyses by a single sting, directed at the common mass of the nerve centres in the thorax. But open a cricket, and what do we find to animate the three pairs of feet? We find what the Sphex knew long before the anatomist, three nerve centres far apart. Thence the fine logic of the three stabs. Proud science! humble thyself.

  Crickets sacrificed by Sphex flavipennis are no more dead, in spite of all appearances, than are Weevils struck by a Cerceris. If one closely observes a cricket stretched on its back a week or even a fortnight or more after the murder, one sees the abdomen heave strongly at long intervals. Very often one can notice a quiver of the palpi and marked movements in the antennæ and the bands of the abdomen, which separate and then come suddenly together. By putting such crickets into glass tubes I have kept them perfectly fresh for six weeks. Consequently, the Sphex larvæ, which live less than a fortnight before enclosing themselves in their cocoons, are sure of fresh food as long as they care to feast.