Some years after Simon's death a former colleague wrote of him that he never took part personally in any ‘close epidemic inquiry’, and failed to understand how much time and work was called for. This judgement was presumably based on personal observation, yet it is difficult to believe, studying the reports of the investigations carried out by his team of four vaccination inspectors, that he could have remained unaware of the labour involved in collecting the information.

One inspector's annual report showed that during the year under review his inquiries had extended over the counties of Cambridge, Derby, Huntingdon, Leicester, Northampton, Warwick and Notting - ham. This territory included 93 unions, subdivided into 457 vaccination districts. He had conferred with 373 public vaccinators, 235 sub-district registrars, the majority of the ministers of religion and with ‘many people of influence living in the different districts’. He had personally examined the conditions as to vaccination (i.e. the marks on the arms) of 46,871 children in national, parochial, workhouse and other schools, and of ‘a great many in and about the dwellings of the poor and neglected’, classifying them as ‘good, indifferent or bad’. In another year the same inspector, Dr Stevens, was allotted as his sphere of operation the 79 unions in the West Riding of Yorkshire, Lancashire, Cheshire and part of Cumberland, ‘embracing a population of 4,498,695, extending over 3,697,342 acres, divided into 507 vaccination districts [served by] 511 public vaccinators and 366 sub-district registrars’. In addition to the routine work of inspecting the quantity and quality of vaccination marks, if any, of all the children in this vast area,