About 400 volunteer firemen from 25 area companies battled a spectacular fire in Slatington this evening, which destroyed an entire row of houses and left 32 people homeless. The fire, which raged out of control for more than four hours, gutted the nine row houses in the 200 block of Oak Alley. Fire officials said they will investigate to determine the cause of the fire, but believe it was started by a parlor heater of one of the residents.