3. From great trocbanter to the opposite sacro-iliac joint, 10 to 12 inches.
4. Depth of pelvis from top of sacrum to coccyx, 4 to 5 inches.
From the first of these, according to Bau delocque and Velpeau, 3 inches must be de ducted for the thickness of the parietes, and from the second 4 inches. Boivin and Lacha pelle doubted the utility of these measure ments generally, because of the great varia bility in the thickness of the pelvic walls; and Dr. Davis has more recently found the thick ness of the base of the sacrum to vary from 2 to 3 inches in 17 dead subjects.
The measurements of Naegele and Otto, with a view to determine the presence of obliquely deformed pelves, are of great im portance in the practice of midwifery, and rnay be best given in this place. Out of forty two female pelves of medium size, the best formed they could obtain, these observers found the following measurements :— Danyan, pursuing Naegele's system, found the great rarity of perfectly regular female pel ves. Out of eighty female pelves he found fifty nine differ, in the first measurernent, from 1 to 6 lines. In the second measurement he found
a difference, in fifty-eight pelves, of 1 to 11 lines ; in the third, fifty-one differed from 1 to 7 lines ; in the fourth, sixty-tu o from 1 to 9 lines ; and in the fifth measurement, forty eight pelves had a difference of from 1 to 9 lines. The table on the next page shows the great variety in the diameters of female pelves which may be considered as normal pelves. In males Dupuytren found the distance between the tuberosities of the ischia, in twenty-three subjects, to vary frotn 2 to 31 inches; and Velpeau, in forty subjects, to vary from 11 to 4 inches. In fourteen subjects I have found the least distance to be 3 inches, and the greatest 4 inches in the male, and mea.suring from the exact centres of the inner margin of the tuberosities. These observations on the male are of some im portance with a view to the operation of lithotomy, when the stone is of great size.