Our cough syrup in those days was something doc had great faith in. All I remember about it was that it was clear (it was in a clear glass bottle as well), burned like crazy going down, and had a sort of turpentine or kerosene "whang" to it. One did not look forward to the stuff, but it apparently did the trick.
YOU are talking about Elixer of Terpin Hydrate, made by McKesson...(I remember the bottle, too) LOL..and it burned worse than a shot of everclear!