At first glance, one might think this dog couldn't stop smiling. In fact, the dog's facial muscles were contracted, thus pulling the lips back into what looks like a "sardonic grin." Excess salivation was caused by the dog's difficulty in swallowing. Note that the dog's ears are pulled back; this too is due to a spasm-like contraction of voluntary muscles. The muscle contraction is apparent along the dog's neck and back, and also in the straddle-like stance of its front and back legs, which it develops to keep from toppling over. The dog's eyes are somewhat sunken, with a result that the third eye-lid has begun to prolapse, or extend visibly over the eye.