stitutes for the leaves of the mulberry ; while the Arindy silk-worm of 
India, Phalena Cynthia, feeds upon those of the castor-oil plant, Ri- 
cinus communis, belonging to Euphorbiacee. Considering that a cir- 
cumstance of this nature was not likely to be accidental, I was induced 
to think that it depended upon the presence of some principle com- 
mon to all these vegetables, and therefore that caoutchoue (perhaps in 
a modified state) might really be contained in the juice of the mulberry, 
though this is described as not being milky. I therefore requested Mr. 
Sevier, who has made so many discoveries in the properties of caout- 
chouc, to ascertain whether my conjecture was well-founded. Ina 
few days he informed me that the mulberry-tree sap was of a milky 
nature,’and did actually contain caoutchouc, especially on dry and 
bright sunny days.” 
Since this was written it has been stated in the newspapers, that a 
species of Scorzonera, which belongs to the natural family of Cicho- 
racee, has been found a good substitute for the mulberry leaf, in 
France. We have also been informed that a caterpillar which forms a 
very large cocoon, and spins a tough but coarse kind of silk, feeds on 
the leaves of the South-American caoutchouc tree, Siphonia elastica. 
This is but one of the important and interesting results which may be 
expected to follow from studying and arranging plants in groups, ac- 
cording to their affinities, as has been attempted by what is termed 
the Natural Method. Led away by the apparent simplicity of an 
artificial arrangement of plants, botanists neglected the strong proofs 
furnished by the instinetive propensities of the whole animal kingdom, 
that plants which agree in structure generally possess similar proper- 
ties. It was long known that certain animals fed on particular plants, 
and both during the last century and the present, this fact has been 
adduced as an evidence of the paternal care of the Creator, in provi- 
ding food convenient for all his creatures, “so that each should have 
its allotted portion” (See Stillingfleet’s Tracts ; Art. “The Swedish 
Pan,” translated from the Pan Suecicus, in Ameenitates Academice, Vol. 
II; also, Church of England Magazine, Vol. III, p. 211); but it is 
available also to shew the correctness of botanical analogies. In this 
way has Decandolle (Essai sur les Propriétés Médicales des Plantes) 
applied it, and it is so much the more convincing, that the proof is thus 
drawn from a source incapable of bias or prejudice. A few of the 
examples may be quoted. The Cynips Ross, and Cynips Salicis, the 
Cionus Scrophularie, and Hypera Rumicis feed upon several, some- 
times all, the species of the genera of plants mentioned; but upon no 
