This has quite an interesting warning - that we could revert to the evil tactics of using poisoned gas as a tool of warfare; and with the Nazi menace already looming in Europe when this was made in 1938, it has added poignancy. Eliot Makeham ("Prof. Grayson") is a scientist who has designed a formula that can provide a proof against such gases; but the duplicitous Noel Madison ("Dr. Klee) has his eye on it. John Loder ("Capt. Grant" ) is the plucky MI5 guy who has to ride to their rescue. It has a little intrigue at the start, and isn't terrible, but the script and direction are all pretty rout... read the rest.