Climax refers to the highest point in the development of a story. As such, the climax in this story lies in Harry Pope's completely unexpected tirade against doctor Ganderbai. His reaction to the good doctor's slightly sarcastic question about whether he had actually seen a snake is met with a surprisingly violent and vehement outburst from him. What makes this ironically surprising, even shocking, is that Harry does not show any gratitude for the dedication that the doctor displayed in his attempts to ensure his safety. He seemingly takes it for granted that the doctor had to know that there wasn't a snake, whilst, ironically he, the supposed or possible victim, had been lying still for hours without knowing any better.
Harry's outburst is completely inappropriate and displays arrogance and prejudice. The true poison in the story is exactly that: his vile, vehement and unfounded prejudice. The discovery that there was no snake at all is an anti-climax.
The theme in this story is fear and paranoia. More specifically, it is about fear bred from a limited understanding of what we know. Both Timber Woods and Harry Pope have a rudimentary knowledge of the dangers a krait poses. Their understanding is based on what they have heard and on rumor. None of them has ever been involved in a direct confrontation with such a poisonous snake. Because of this, they are both desperately afraid and in a quandary about how to deal with this supposed threat. They, therefore, need the assistance of an expert who is presented in the form of the knowledgeable and kind Dr. Ganderbai who is more than willing to sacrifice his time and resources to help a fellow human whom, he believes, is in desperate need.
This act of kindness is, however, lost on our much-relieved victim, Harry Pope. He allows his prejudice to come to the fore when he expresses his vehemence on the undeserving doctor. Just as much as his knowledge about exactly how to deal with the supposed snake was limited, so is his understanding of the doctor. One may assume, when one takes into account their names, that they are of a different race to the doctor who is clearly Indian. Harry's prejudice is borne of a supercilious attitude. His outburst is completely unwarranted and hurtful.
The story is told from a first person, limited perspective. Timber Woods is the narrator and he reports in the minutest detail all the aspects relating to Harry's unfortunate position. All he can comment on is what he witnesses and, obviously, his own feelings. Timber is not critical or judgmental. He, however, does share Harry's anxiety. He does apologize on his friend's behalf after Harry's vile tirade. His judgment of Harry is clearly based on his concern for him, for he says that his outburst was as a result of the enormous stress that he had suffered throughout his ordeal.
The tone of a story refers to the writer's attitude towards a character, place or development. Roald Dahl's tone is clearly satirical. The fact that he chose such archetypal names as Timber Woods (quite humorous), Harry Pope and Dr. Ganderbai, clearly supports this. Furthermore, in depicting what is actually a harmless situation in such a serious and dramatic manner, Dahl emphasizes his scornful attitude. He clearly makes fun of the irrational fear that others, who deem themselves superior, hold of things they obviously do not understand. This fear is expressed through prejudice - it is a protective mechanism.