"The Stolen Bacillus" by H.G. Wells is a satiric short story about the potential dangers posed by the world of science. Satire is using humor or wit as a form of ridicule which exposes flaws or faults in mankind or his institutions; the intention must be to help improve either man or the institution. In this story, Wells is satirizing the institution of science as well as the role of anarchists in society.
The atmosphere of "tension and fear" is created from the beginning in several ways. First, of course, is the consistent mention of the dread word: cholera. Just the word conjures up images of death, horrible suffering and the plague. We are afraid of what might happen, even though the bacteriologist assures us that these specimens "have been stained and killed" and are therefore no longer dangerous.
Second, the mysterious visitor to the lab is consistently described as "the pale-faced man," something which conjures a mystery of danger and intrigue.
Third, the deadly virus is being kept in a tube, a tube which keeps readers just a little breathless with anticipation because we know a little glass tube can easily be broken or stolen--and both things eventually do happen.
Fourth, we begin to see a transformation in the pale-faced man as we see a gleam in his eyes as he becomes more and more mesmerized by the sight of the deadly bacteria in the tube, "devouring the little tube with his eyes." It is especially chilling when he begins to recite the litany of ways in which the deadly virus might be silently transmitted to every person and animal. The more he talks, the more we know that this is not only something he has given much thought to, but it is something he almost anticipates with delight.
Note the language of death in this description:
Only break such a little tube as this into a supply of drinking water...and death - mysterious, untraceable death, death swift and terrible, death full of pain and indignity - would be released upon this city, and go hither and thither seeking his victims.... He would follow the watermains, creeping along streets, picking out and punishing a house here and a house there where they did not boil their drinking-water, creeping into the wells of the mineral-water makers, getting washed into salad, and lying dormant in ices. He would wait ready to be drunk in the horse-troughs, and by unwary children in the public fountains. He would soak into the soil, to reappear in springs and wells at a thousand unexpected places. Once start him at the water supply, and before we could ring him in, and catch him again, he would have decimated the metropolis.
The word "death" is repeated for effect, and then it is personified as a person who goes, seeks, takes, creeps, lies in wait, appears and disappears, punishes and eventually "decimates." There is a cumulative effect to these words and images, and our sense of fear and doom increases until it reaches a crescendo of destruction--an entire city has been destroyed. This could happen.
As we feared, the man steals the tube and runs; and we know exactly what will happen because he has told us. The satire (wit and humor) happen once the desperate, life-and-death chase ensues. The scientist is a ridiculous figure who runs off half-dressed, and the chase is a spectacle that the cabbies place bets on. We are horrified that the tube breaks, unleashing destruction, until we discover it was not cholera and the man is likely to turn blue--like a monkey. Science looks just as foolish.