The larvae are killed and hardened by steeping some hours in strong acetic acid; the silk glands are then separated from the bodies, and the vis cous fluid drawn out to the condition of a fine uniform line, which is stretched between pins at the extremity of a board.
As the steeping is such a critical operation, it is essential that the stalks be frequently examined and tested as the process nears completion.
Claussen's process consisted in steeping flax fibre or tow for twenty-four hours in a weak solution of caustic soda, next boiling it for about two hours in a similar solution, and then saturating it in a solution containing 5% of carbonate of soda, after which it was immersed in a vat containing water acidulated with z% of sulphuric acid.
Since these results appear to be satisfactory, it is natural to expect further attempts with the same object of supplanting the ordinary steeping.
It is thereafter once more tied up, placed in the crates, and sunk in the river to complete the retting process; but this double steeping is not invariably practised.