The planting of them was much encouraged by King James I. about 1605; and considerable attempts were made at that time to rear silkworms on a large scale for the purpose of making silk; but these endeavours have always failed, the climate being scarcely warm enough.

But if, on the other hand, the Panhistophyton is an independent organism, which is no more generated by the silkworm than the mistletoe is generated by the apple-tree or the oak on which it grows, though it may need the silkworm for its development in the same way as the mistletoe needs the tree, then the indications are totally different.

The Mussel which makes such long anchor-threads might be called "the silkworm of the sea.

During the reign of Justinian two monks brought the eggs of the silkworm to Byzantium from Serinda in India, and the manufacture of silk became a royal monopoly of the Roman Empire.