For the 11-year-olds setting out on the biggest educational adventure since starting school, it's the very size of the secondary school, with its endless corridors, countless doors and its huge people that sets small hearts a-flutter.
A mythology can grow up around the transfer, fuelled by first-year pupils who for the first time sense that they are the cognoscenti, the experienced people who tell it as it is.
Injections seem to have claimed a prominent position in this folklore of transition. I have been asked by primary pupils "Is the BCG sore?", "When do you get the jab?", revealing a hypodermic phobia which seems to be passed on down the years like a contagion.
I enjoy going into primary schools and experiencing the enthusiasm and anticipation of our new recruits. If you care to join in circle time at St Ninian's, they will give you a rapid evaluation of your school, just as accurate as the scrutiny of HMI. "My big sister says she is doing the Romans, and she did the Romans last year."
There are familiar faces, the red-headed sibling of a Holy Rood rogue, the big specs of yet another progeny of a studious clan. Their preoccupations are pragmatic. "Is it true you get chips only on a Tuesday?" One wee girl commented: "Mr Sweeney, I love your uniform!" "You mean our new school sweatshirt?" I enquired with proprietorial pride. "No, sir, I mean your suit," she replied.
There is a tradition that guidance teachers offer a family interview to every P7 graduate. This worked well when the intake hovered around 90, and we had a horizontal guidance system. We now have a vertical arrangement, with every guidance teacher having a constituency in the new year group.
The vagaries of the parents' charter make it more difficult to know who will turn up for our two-day induction session. There are 32 primary schools on the list, but some parents have made placing requests for three or four schools and keep us in suspense.
The new arrivals will meet their form teachers and have a timetable for both days, involving an orienteering exercise. Primary staff remain on hand to provide reassurance and occasional words of comfort - or admonition - as the situation demands.
The parents' evening for the new intake takes place the next day, and families arrive with tales of the two-day induction and the new world of the secondary school. Parents are often more apprehensive than the children, but they are quickly reassured by the gentle tones of assistant head Wendy Doran, who looks after first and second year. We sell huge quantities of school uniforms and PE kits, with the occasional parent trying on the school sweatshirt, a bargain at pound;12.
The tour of the school shows parents how things have changed since their own school days. A remarkable number reveal that they too went to Holy Rood and can remember Mrs Phanjoo, Mr Demarco and others.
When we next see the new pupils, they will be bustling along the corridors, indistinguishable from the hundreds of others already in our care. Before long, they will move through the school and become the giants they feared on those first anxious days. In their sixth year, they will be assigned to look after a group of Primary 7s, who will assail them with questions about injections and chips.
Pat Sweeney is headteacher of Holy Rood High School, Edinburgh