Steinbeck begins by describing the town as an animal, comparing it to an animal in order to stress how the town has a rhythm of its own.
A town is a thing like a colonial animal. A town has a nervous system and a head and shoulders and feet. A town is a thing separate from all other towns, so that there are no two towns alike. And a town has a whole emotion. (ch 3)
Steinbeck is reminding us that the story takes place in a village, and villages have a different social structure. A village is an entity, a life form, in and of itself. The town thinks- it has a nervous system and a head. News seems to travel on its own. Towns like this also feel; they have their own emotion. This stresses the cultural aspect of the town, and its uniqueness. The people of the town act as one.