[Footnote: M. Velpeau (Nouveaux Elemens de med. Operat.) states the length of the inguinal canal in a well-formed adult, measured from the internal to the external ring, to be 1-1/2 or 2 inches, and 3 inches including the rings; but that in some individuals the rings are placed nearly opposite; whilst in young subjects the two rings nearly always correspond. When, in company with these facts, we recollect how much the parts are liable to be disturbed in ruptures, it must be evident that their relative position cannot be exactly ascertained by measurement, from any given point whatever. The judgment alone must fix the general average.] [Illustration: Abdomen and scrotum, showing bone, blood vessels and other internal organs.] Plate 42--Figure 5 [Illustration: Abdomen and scrotum, showing bone, blood vessels and other internal organs.] Plate 42--Figure 6 [Illustration: Abdomen, showing bone, blood vessels and other internal organs.] Plate 42--Figure 7 COMMENTARY ON PLATES 43 & 44. THE DISSECTION OF FEMORAL HERNIA, AND THE SEAT OF STRICTURE. Whilst all forms of inguinal herniae escape from the abdomen at places situated immediately above Poupart's ligament, the femoral hernia, G, Fig. 1, Plate 43, is found to pass from the abdomen immediately below this structure, A I, and between it and the horizontal branch of the pubic bone. The inguinal canal and external abdominal ring are parts concerned in the passage of inguinal herniae, whether oblique or direct, external or internal; whilst the femoral canal and saphenous opening are the parts through which the femoral hernia passes. Both these orders of parts, and of the herniae connected with them respectively, are, however, in reality situated so closely to each other in the inguino-femoral region, that, in order to understand either, we should, examine both at the same time comparatively.