Henry McGee plays the salesman for a stationery firm. He refers to his manager as Mr Pugh, which Steed repeats with emphasis. Mr Pugh was the character from Charlie Drake's 'The Worker' which McGee was best known for playing at the time.
Fuddy duddy Dr. Fawcett starts to comment on how chloroform, when exposed to light and air, oxidizes to... It oxidizes to phosgene, the most potent poison gas used during WWI trench warfare.