The three friends are shown to be rather disorganised in the way that they pack for their trip.
Jerome forgets to put in various items, which have to be pointed out to him by the others. Then he gets worried that he’s forgotten to pack his toothbrush. He confesses his toothbrush ‘is a thing that haunts me when I go travelling and makes my life a misery’ (chapter 4). He is always looking for it and packing and unpacking it when he’s preparing for a journey. On this occasion, he does find it, but he has to unpack everything again to do so.
Jerome, then, comes across as rather absent-minded and forgetful in his packing. George and Harris are even worse. They pack the hamper after Jerome has finished packing the other things, and they make a mess while doing so. They manage to sprinkle salt over everything, butter gets smeared everywhere, tomatoes get squashed, and so on. To make matters worse, Montmorency, Jerome’s very badly-behaved terrier, gets involved. George and Harris reveal themselves to be haphazard, indeed quite chaotic in their packing.
As so often in this book, the packing scenes are used to great comic effect. We get a picture of the three men as blundering, albeit well-intentioned types, always getting in each other’s way and unable to complete any task in an orderly fashion.