


238 THE BRITISH FERNS. 
account of their richness in mineral constituents, and in nitrogen. 
According to Sprengel, the fresh gathered fronds, air-dried, contain 
in 10,000 parts :— 
Silica . 
Lime 
Magnesia 
Potash 
Soda 
Alumina . 
Oxide of iron 
Oxide of manganese 
Sulphuric acid 
Phosphoric acid 
Chlorine 
So that upwards of one-third of their bulk consists of mineral 
substances. Sprengel also states that the dry herbage is rich in 
nitrogen. This useful manurial quality is not a recent discovery, 
for Lightfoot, already quoted, has recorded that on account of the 
great quantity of alkaline salts in its composition, Fern is a great 
improver of land; and that when used for manuring potatoes it 
never fails to produce a good crop. 
The stout underground caudices or stems (or ‘roots’ as they are 
often called) are not unfrequently used as food for pigs, these animals 
being very fond of them. The young fronds are also employed for 
the same purpose; they are gathered when quite tender, and boiled 
or simmered for a couple of hours in water, the liquor thus obtained 
forming when cold a strong jelly, which appears to be equal in value 
to potatoes for pig-feeding. The mucilaginous mass obtained in this 
way, by boiling the green fern sprouts, will keep for a considerable 
time; and Mr. Lees states* that the cottagers find it very ser- 
viceable, from its coming in at a time when garden refuse produce 
available for the pig-stye, has become scanty. He suggests also, that 
a dish of boiled Péeris in its circinate state might not be very un- 
palatable with a rasher of bacon to a hungry man. 
The succulent underground stems both of the Common Bracken, 
and of some of its varieties or near allies which inhabit various 
parts of the world, have been used as food for man. The fern 
* Lees, in Phytologist, i. 263. 

