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.
By this method the operation of steeping is entirely dispensed with, and the flax is, immediately after pulling, spread on the grass where it is under the influence of air, sunlight, night-dews and rain.
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.
" It may be remarked," says Mr Andrews, " that the superiority claimed for this method of retting flax over what is known as the `hot-water steeping' is uniformity of temperature; in fact the experiments have demonstrated that an absolute control can be exercised over the means adopted to produce the artificial climate in which the vats containing the flax are situated."