The degree of heat treatment is closely related to the quality of specimen preparation. If the heat treatment time is too short, it will be very troublesome and the effect will not be good. If the heat treatment time is too long, the connecting ligament between bones is easy to be scalded, and the bones are scattered and difficult to assemble. Therefore, we should pay attention to the following issues:
(1) The length of heat treatment should be different according to the size of the fish. Big fish have a long time, but small fish have a short time. If the fish scales are large, you can scrape them off with a knife and then scald them.
(2) Don't scald the whole fish in boiling water for too long, just tear off the fish scalp. After a long time, the skull and fins are easy to be boiled off and fall off. It is not easy to repair the fallen skull.
(3) Fishing fish from boiling water with fences or other suitable tools, and pulling the fish head, tail or fin directly will easily damage the specimen.
(4) If you can't master the degree of scalding at one time, you can scald the fish skull and fins several times without being scalded, that is, remove some muscles after scalding and then scald them again.
Remove muscle
Because the bones of fish are relatively small, it is impossible to remove all the muscles at the bones and ligaments, but try to remove them as clean as possible. Abdominal viscera should be removed after abdominal wall muscles are removed, and ribs should not be damaged. Removing muscles is a meticulous job and cannot be sloppy. We should operate on the basis of understanding the fish structure, especially the bone structure, and operate carefully to avoid damaging the bones.
The order of muscle removal is trunk, tail, head and fins. When removing muscles, pay attention to protecting fish heads, fins and fishbones. Only the muscles outside the operculum are removed from the head. Except for special needs, the muscles covered by the bones outside the fish head should not be treated.
(1) Rough machining uses tweezers to gently tear off the muscles in the abdomen and tail of the fish along the bone direction, leaving only the spine and ribs, and removing the small bone spurs between the muscles that are not connected with the spine. The fin bone of the branch of gluteal fin is connected with the venous spine of coccygeal vertebra and should be protected. To remove the pelvic fins together with the belt, remove the muscles and skin separately. Larger fish can cut large muscles from the back to the abdomen with a knife, and then remove the muscles attached to the bones with a knife and tweezers.
(2) Carefully remove the small muscles attached to the bones, especially the muscles behind the head and above the vertebrae, with small tweezers and scalpels. The cleaner the better. Don't let the knife hurt the bone. Small parts can be gently brushed off with a brush (preferably a toothbrush) in water.
(3) The treatment of the head and fins is mainly peeling. The skin on the head and fins of scalded specimens can be brushed off with a brush, and the muscles outside the bones of the head can be clipped off with tweezers. The bones in the fish mouth and eye socket are relatively small and easy to be damaged, so brush lightly and remove the skin. When brushing the skin of the fin, the brush should be brushed gently from inside to outside along the direction of the fin to prevent the fin from breaking and causing irreparable losses.
Corrode muscles
This is a continuation of the previous step. Knives, tweezers and brushes are difficult to remove the muscles attached to the bones, and the remaining muscles should be treated with alkali again to make the bones cleaner.
Immerse the sample in 0.5 ~ 1% sodium hydroxide solution 12 ~ 24 hours. In the course of treatment, we should always observe the changes of specimens. After the remaining muscles on the bone are transparent, they should continue to be treated, which is equivalent to 1/4 of the previous treatment time, then take them out, soak them in clear water, and then brush them off with a brush.
Alkali has a strong corrosive effect on muscles, so the progress of alkali treatment must be observed frequently. If the treatment time is too long, alkali will melt all the ligaments and muscles connecting the bones, making the bones become a pile of broken bones, losing their use value and giving up all previous efforts.
degrease
(1) dehydration will drain the water from the specimen, and the water in the specimen will be removed after being treated with 95% and 100% ethanol for 2 ~ 3 hours respectively (for specimens with large bones, the treatment time will be prolonged). Or dehydrate by natural drying.
(2) Degreasing: Immerse the sample in xylene or gasoline for degreasing 1 ~ 2 days.
(3) The rehydrated water is naturally dried and then returned to the water or returned to the water through 100% ethanol and 95% ethanol.
bleach
Soak the specimen in 2 ~ 3% hydrogen peroxide or 0.5% sodium peroxide solution 12 ~ 24 hours, take it out when the specimen begins to turn white, and rinse it with clean water.
7. Plastic installation
Specimen can be shaped and mounted in one step, or it can be shaped first and then mounted after the specimen is dried and hardened.
(1) plastic shelves can be completed in one step. Take a wooden board with a length greater than 1/3, a width of 15cm and a thickness of 1.5 ~ 2cm as the bedplate. Put the fish skeleton in the center of the bedplate, and mark the positions of the rear edge, ventral fin and caudal fin of the fish head on the bedplate. Punch 0.2 cm holes in three places marked on the bedplate. A thin iron wire with a diameter of 0. 1 cm is wound around the front and back of the spine and the ventral fin, and then fixed on the bed board. Because there is no dry specimen, it is easy to deform, so the installed specimen should be tied to the dorsal fin and spine with 4 ~ 5 cotton threads and pulled up to make the specimen in a natural state. After the specimen is dried and the shape is fixed, the cotton thread can be removed.
(2) After setting, put it on a shelf, take a foam plastic board or cork board longer than fish, and a plurality of long needles (toothpicks are also acceptable). Clamp the fish head back and forth with two needles, hang the fish skeleton on one side of the foam plastic board, and fix the deformed part into a natural state with needles. After drying, take out the needle, take out the specimen and install it. Mark the rear edge of the fish head, the ventral fin and the middle of the coccygeal vertebra on the bed board, and punch holes with a diameter of 0.3 cm. Insert the same thick bamboo stick into the small hole, determine the height of the three pillars with the specimen, cut the upper end into a plane, add a drop of all-purpose glue (or gelatin), and then gently put the specimen on. Temporarily fix the sample, dry the glue, and remove the fixing frame.
If there are ribs falling off in the process of making specimens, we should pay attention to keeping them and deal with them together all the time. After the specimen is mounted and dried, it is glued in place with universal glue. Finally, label the specimen with a skewer.