Douches to the spine are much employed for nervous debility, and good effects are also obtained in such cases from the so-called needle-bath, where small streams of water at high pressure are driven against the whole surface of the body.
In 1816, 1817 and 1818, he published a series of Quarterly Reports of Cases in Surgery; in 1821 a volume of coloured plates with descriptive letterpress, entitled Illustrations of the great operations of Surgery, Trepan, Hernia, Amputation and Lithotomy, and in 1824 Observations on Injuries of the Spine and of the Thigh Bone.
Following the metasoma in Limulus, we have as in Scorpio the post-anal spine - in this case not a sting, but a powerful and important organ of locomotion, serving to turn the animal over when it has fallen upon its back.
In some individuals the dorsal fin is only half its normal length, in others entirely absent; in others the anal fin has a double spine; in others all the fins are of nearly double the usual length.
The spine is very slightly developed; rather above the middle its edge is thickened and somewhat turned backwards, but it gradually subsides at the lower extremity without forming any acromial process.