Bear in mind that the volume of water containing the specimen will have an effect on the time and efficiency of the narcotizing agent. Specimens treated overnight are perhaps simplest to deal with, in that you do not disturb them by constantly probing and pinching. Occasionally, specimens are completely insensitive to severe pinching and probing but, nevertheless, contract when placed in formalin. Perhaps the best results are obtained by the alcohol method, fair results being obtained with the menthol, Chloretone, or clove oil method. When combined with the alcohol technique, menthol gives good results.
For the alcohol method, place specimens in a container of sea water large enough to permit expansion. Add 75 percent alcohol, drop by drop, until the worms become insensible. Stop the procedure when enough alcohol has been added to equal about 10 percent of the water or when the sea water becomes slightly milky. Test the worm by gently probing and, finally, by pinching the posterior end with forceps. If the worm continues to be active after the alcohol is introduced, test the worm each hour until the specimen is insensitive. When the worm no longer responds, stretch it out on a roughsawed board and add a small quantity of FAA (Appendix C, use Bouin’s Fixative for histological specimens) to the specimen. After a few moments stretch the specimen out in a pan of FAA for 24 hours. Preserve as directed below.
Tube worm and all free-living form may also be treated with method. Place specimens in finger bowls two thirds full of sea water, and sprinkle menthod crystals on the surface and cover. This will produce beautifully expanded worms, though 12 hours to 24 hours may be required for complete narcotizing of the specimens. When relaxed, tube worms can be withdrawn from their tubes and fixed as directed above. After they have been in menthol a few hours, alcohol can be introduced, as directed above, with excellent results.
A few drops of cover oil placed in a finger bowl or Petri dish containing specimens tends to render specimens insensitive more quickly than any other compound. However, clove oil has two drawbacks : (1) it will irritate specimens that contact it directly and cause local contraction, and (2) insensible specimens often react to FAA. Probably a clove oil-alcohol combination would work quite well.
Epsom salts give mixed results, some specimens being completely narcotized, whereas others periodically revive. One large plume worm in the