Statistics from the British Isles on the incidence of hernia on a large scale are few. Certain facts have been stated and textbooks have repeated them without confirmation. To verify or impugn the accepted figures we have undertaken to investigate 1018 cases of hernia presenting themselves at the Out-Patient Department of the Hospital for Sick Children, Great Ormond Street. The period covered incluides the years 1919, 1921, 1922, 1923, and 1924; and concerns the children up to the age of three years presenting themselves with inguinal hernia duiring this period. As regards umbilical hernia all cases during this period up to the age of 12 years were investigated.Incidence of Hernia in Children of the Hospital Class. The number of new out-r,atients during the five years was 130,243, and of these 1018 were suffering from hernia of some variety, that is, an incidence of 0 8%/1. The ,ex incidence showed 838 males (790/) and 180 females (21%). Inguinal Hernia. Out of 1018 cases there were 773 simple inguinal herniae. 696 cases were males and 77 were females, that is, 90°/0 were males and 10% females.Operations and Recurrences. Out of the 773 inguinal hernise, 564 were operated upon, with 4 recurrences. This is a proportion of 0-70o. Of the 209 cases which were not operated upon, in 185 the hernia had apparently spontaneouslv disappeared, while in 24 the hernia was still present, but not operated upon for some special reason of the parents or the condition of the child.Jncidence of ,Spontaneous Cure of Inguinal Her,nia. Out of the total of 773 inguinal herni~e investigated, 185) disappeare(l spontaneously. This is 2400/ or one quarter did not requiire operation.The chances of a spontaneouis disappearanice of an inguinal hernia would appear to be better in fenmales than in males, since in 3700 of females but only in 22o/ of inales did this occuir.That these figures represenit only apparent cuires must be emphasized as in contrast to umbilical hernia u'here one can by a truss or pad invaginate and therebv obliterate the sac, thus being certain of cutre, in inguinal hernia the -ord cure " merely signified in many cases a fibrosis of the neck of the sac, a potential herniial sac still existing. It may be that from these apparent cures arises that class of case in which followinig on some unuisual exertion, a scrotal hernia suiddenly develops in a voung adult.Age at which Spontaneous Disappearance Occurred. As far as could be ascertained the inguinal hernive disappeared usually before the age of one year, but in some the hernia recurred at intervals up to the age of three years.