A two-year-old Border Terrier kept whipping his head around to look behind him, as if something had moved. Sometimes he snapped at the air. Then he would hide, stare into space, and briefly seem to switch off.
A one-year-old poodle mix licked his lips, stared, and snapped at things nobody else could see. A four-year-old mixed-breed dog became anxious and unusually clingy, made repetitive mouth movements, and drooled clear saliva from the right corner of his mouth only, enough to leave the fur on that lip visibly wet.
