Possible Clues:

• Amusement caused by it in the course of Spring term at Oxford
• Unrestrained mirth
• Funny sort of term to spring on them around it at university
• The stuff of 21, 15 24 and 10 - girl bottles it
• Mirth shown by girl receiving it
• Fun is just what one wants in a term at Oxford
• There's a lot of laughter when a girl swallows it
• Laughter is just the job during term
• Term used about it produces merriment
• Comedy greetings artily laid out