Sentence:  Ultrasound as a treatment for degenerative arthritis was in its infancy. It might eventually turn out to be as effective as the Salk vaccine, or as bogus as the science of phrenology. Either way, it didn't make sense right now. The chances were a thousand to one that it was a <WSD>dry hole</WSD>. 
Meaning of the word marked with <WSD> tags:  Something that brings no success or profit; a dead loss.