842 
THE PRINCIPLES OP BOTANY. 
those too closely allied to be as yet distinguished are often 
met with where disease is not present. 
It will be right in this place to glance at some of the 
confervoid plants which occur in different chemical solutions; 
thus, if mucilage of the quince-seed be set aside for a time, it 
becomes the home of a plant, so solutions of tartar emetic, 
solutions of mixed polychrome and sulphate of copper, of 
phosphoric acid, and others, on being exposed, soon become 
filled with what, to the naked eye, appear like masses of jelly 
or agglomerated fibres of cotton. These, on being placed 
under the microscope, present us with evident signs of vege¬ 
table structure; but whether such minute plants are to be 
regarded as the spawn or mycelium of different moulds, or as 
true algae, it is at present difficult to determine. 
We may here notice that several species of marine alga3 
are used as food, such as the 
Porpinjra lacmiata —Laver. 
TJha latissima —Broad green laver. 
Laminaria digitata —Sea-girdler. 
Alaria esculenta —Honey-ware. 
Of these the two former are Confervee, but the latter are 
Fucoids, and only here placed because they are sometimes 
referred to under the same designation. The similarity in 
structure to that of the Sarcinawill be gathered from the fol¬ 
lowing description:—Under the microscope the whole form 
appears to be divided into squares in the manner of a tesse- 
lated pavement, and within each square are four purple 
granules or spores, which constitute the fructification and the 
whole colouring matter of the frond. Abundant on all our 
shores, this plant is pickled with salt, and sold in London as 
laver. The London shops are said to be supplied with it from 
the coast of Devonshire. When stewed it is brought to the 
table, and eaten with pepper, butter, or oil, and lemon-juice 
or vinegar. Some persons stew with leeks and onions. It 
is generally taken as a luxury; but it might be employed 
with advantage by scrofulous subjects, as an alterative article 
of diet. In the absence of other vegetables, it might be valu¬ 
able as an anti-scorbutic to the crews of our whaling vessels 
cruising in high latitudes, where every marine rock at half 
tide abundantly produces it.* 
The Fticacece, or sea-weeds, form a large and very important 
class of plants, which are distributed in the marine waters of 
all parts of the world they are described as cellular or tubu¬ 
lar algals, propagated by spores (endogenous cells), contained 
in superficial, often bladdery (tiiricles) cells, produced singly 
* See Pereira’s ‘ Materia Medica.’ 
