BRITISH FERNS. 
IT2 
worker, or cabinet-maker could complete his work 
without “Dutch rushes” as these horsetails are called, 
to polish it, and even now large quantities are'im¬ 
ported from the marshes of Holland for this purpose. 
The presence of the siliceous substance so valuable in 
the stems of these plants can readily be seen under a 
microscope, and a very favourite object for display is 
a section of one of these stems, in which the silex may 
be observed arranged with the utmost regularity 
along the longitudinal ridges. Sir David Brewster 
shows that each fragment of this material is possessed 
of an “ axis of double refraction.” 
It seems strange that plants of so rough, and rigid 
a nature as these should be used as human food, but 
such is nevertheless the case. Haller tells us that the 
Romans were in the habit of eating the great Horse¬ 
tail, and another more modern author says that “the 
young buds are dressed by some like asparagus, or, 
being boiled, are often strewed with flour and fried, 
being considered a delicacy.” Gerarde recommends 
them in a bruised state for the cure of wounds, and 
tells us that the juice may be drank in order to stop 
bleeding of the nose. It is not improbable that they 
may contain some slight astringent properties, and 
with this view Tragus advises the expressed juice to 
be applied to recent and bleeding wounds and to be 
taken internally as an astringent. 
