THE July issue of the Boletin de la Oficina Sanitaria Panamericana contains an instructive article by Dr. G. Bayley Bustamante, assistant professor of public health, Buenos Aires, dealing with the last outbreak of poliomyelitis in the Argentine (October 1942–May 1943 with 1,948 cases). This was probably the largest outbreak, although epidemics were reported in 1909, 1911, 1916–17, 1919–20, 1924–25, 1932–33, 1934–35 and 1936, mostly in the Buenos Aires and Rosario Area, with smaller outbreaks and sporadic cases in the rest of the country; but paralytic cases figure in the statistics in 1941. There were 355 cases (189 in the Province of Santa Fé), which was an increase on the usual yearly figures. The 1942 epidemic in the southern suburb of Buenos Aires then extended into the city and to the rest of the province, with the peak in November and December; it increased along the coast after January and moved northward. The incidence was highest in the Buenosires sector. Half the cases were in children aged 1–3 and another 10 per cent in those less than 1 year. The death-rate ranged from 3·5 to 23–25 per cent, usually being 10 per cent. Of the eight large Argentine epidemics, four began in February and one each in June, September, October and November. The 1942–43 epidemic had its peak in October–November (spring); the year had been characterized by a hard but short winter, an early warm spring and a very hot and dry summer.