Second, infested billets must be stored and monitored carefully, because the developing larvae are subject to predation from rodents and ants, particularly when the bark splits as it dries.
Wilson's reason was that the transcription of such detail for all the 1,365 billets being used was not possible.
The entry billets, however, permit a more detailed study of the children's backgrounds, giving also more precise information on the characteristics implied by this initial study.
This supposition can be examined with the data from the billets and notes.
Of the 1,650 billets sampled, 299 (18 per cent) included notes which contain information as to the legitimacy of the child.
Any note or token left with the child was kept with the billet, which was folded and sealed and marked with the child's number.
The billet was therefore vital in establishing the child's identity and hospital number, allowing its current whereabouts to be traced.
This source is the entry billet filled in for each and every entrant.
