One hot afternoon, Roger and Gerry set out to see how far they can hike before dark. They hike up the hills but because of the intense heat, Gerry decides to swim instead. Gerry swims and digs up rocks and shells, which he offers to Roger. Roger takes them and then surreptitiously drops them back in the water.
Again, the way that Roger so clearly wants to please Gerry by accepting his gifts is evidence of how close and strong their relationship is, even though Roger isn't human.
Gerry wonders where he can get something to eat. He remembers that Yani lives over the hill and will certainly feed him. Gerry and Roger set off and when they're close, Gerry devises a plan to wake Yani from his afternoon nap: work Roger into a barking frenzy by beginning a game of fetch and then refusing to finish the game. Gerry lets Roger bark for five minutes before approaching the cottage and to his disappointment, Yani is still asleep under his grape vine. As Gerry deliberates as to what to do, Roger spots a cat under Yani's chair and lunges at it. His barks wake Yani.
As human as Roger seems at times, the trick Gerry plays emphasizes Roger's canine tendencies and limited understanding of human affairs. This shows that Gerry knows he can use Roger's nature as an animal to his advantage. Particularly when Roger chases the cat and frees Gerry from having to wake Yani himself, it shows that a dog's nature doesn't have to be in contrast to human desires either.
Yani grins at Gerry and calls for his wife, Aphrodite, to bring out food and drink. He explains that instead of taking his goats out earlier, he tasted a friend's wine. He sighs happily and rolls a cigarette before offering Gerry a small bottle. In the bottle, suspended in oil, is a small dead scorpion. Yani points to the shadow in the oil, explaining that it's the scorpion's poison. He gleefully tells Gerry that if you catch a scorpion alive and kill it in oil, then the oil becomes an antidote against scorpion stings.
Yani surely knows that the scorpion will thrill Gerry, though the truthfulness of his explanation seems questionable. Depending on the oil in question it may provide some relief from pain, but it's certainly not an antidote. Yani's tale then becomes part of the eccentric culture of Corfu, given that others presumably believe this as well.
Aphrodite arrives with food and Yani tells Gerry about a man who fell asleep and was stung in the ear by a scorpion. The man fell down dead. After a while, Gerry excuses himself and accepts Yani's parting gift of grapes. Gerry and Roger eat the grapes in a cool olive grove and when they're finished, Gerry examines the mossy bank behind him. He notices faint circles on the bank and when he pokes at a circle with some grass, he's thrilled when the circle lifts like a trapdoor. Gerry has no idea what made the trapdoor, and decides to call on George immediately to ask.
When Gerry shares his grapes with Roger, it's again indicative of their close and loving relationship with each other. Similarly, the fact that Gerry thinks to run to George with his query shows that George is also becoming a trusted friend and authority on matters like this, which shows that Gerry is finding a sense of community on the island.
Gerry races to George's villa, knocks on the door quickly, and lets himself in. He realizes that George has company; a bearded and immaculately dressed man sits with him. George greets Gerry and Gerry explains the nests he found. George turns to his guest, introduces him as Dr. Theodore Stephanides and an expert on everything, and asks Theodore to take over Gerry's query. Theodore shocks Gerry by shaking his hand and then slowly and seriously suggests the nests might belong to trapdoor spiders. He suggests they go look at them if they're not too far and follows Gerry up the hill.
When Theodore shakes Gerry's hand, it suggests that Theodore will treat Gerry as though they're equals, not an esteemed scientist and a young child. Then, by suggesting that they go look at the nests, it presents the possibility that Theodore is just as curious about the natural world as Gerry is. This will then turn Theodore into an example of what adulthood can be, and specifically show that it doesn't need to be boring.
As Theodore and Gerry walk, Theodore stops to look into a ditch of stagnant water and laments he didn't bring a collecting bag. He follows Gerry without protest up the steep track and when they reach the bank, Theodore confirms that the nests belong to trapdoor spiders. He explains that he's always been curious about how the female spiders know when the male spiders are approaching and don't mistake the males for prey. Gerry and Theodore head back down the hill and awkwardly part ways.
Theodore's lament suggests that he is in many ways an adult version of Gerry: he wishes to spend as much time as possible in nature, learning everything he can about the natural world and the creatures in it. When he mentions that he's curious about how things sound to a spider, it also shows that Theodore has maintained a sense of childlike curiosity.
Gerry is both amazed and confused by Theodore. He knows that Theodore is an esteemed scientist and clearly shares his love of the natural world, but he also treats Gerry like an adult, not a child. Gerry puzzles over Theodore's musings about what trapdoor spiders hear and thinks about what different insects must sound like when they walk over one's roof. He hopes to see Theodore again and is thrilled when two days later, Leslie arrives with a parcel for Gerry. It's from Theodore and contains a pocket microscope and an invitation to tea the following Thursday.
Just as Gerry's friendship with Roger shows that friendship can absolutely grow between species, Gerry's budding friendship with Theodore shows that it can also occur between people of vastly different ages (though Gerry never gives Theodore's age, the real Theodore would've been in his mid-thirties when the Durrells were in Corfu). This suggests that in many ways, age is arbitrary.