“…In two other small but intensively studied series (Davidson, 1959;Nisbet, and Wilson, 1958) the bacteriology of infection is discussed since respiratory infection was the indication for tracheostomy; the incidence of post-operative respiratory infection is difficult to assess. Smythe and Bull (1961) and Cole (1959) found that some patients who had tetanus and who were treated by tracheostomy and I.P.P.R.…”