250 MACERATION, DIGESTION, AND CORROSION. 



543. Caustic Potash, Caustic Soda, Nitric Acid. Boiling, or long 

 soaking in a strong solution of either of these is an efficient means 

 of removing soft parts from skeletal structures (appendages of 

 Arthropods, spicula of sponges, etc.). 



544. Eau de Javelle (Hypochlorite of Potash) (NOLL, Zool Anzeig., 

 cxxii, 1882, p. 528). A piece of sponge, or similar object, is brought 

 on to a slide and treated with a few drops of eau de Javelle, in which 

 it remains until all soft parts are dissolved. (With thin pieces this 

 happens in twenty to thirty minutes.) The preparation is then 

 cautiously treated with acetic acid, which removes all precipitates 

 that may have formed, dehydrated, and mounted in balsam. 



The process is applicable to calcareous structures. 



545. Eau de Labarraque (Hypochlorite of Soda) may be used in 

 the same way as eau de Javelle. Looss (Zoo?. Anzeig., 1885, 

 p. 333) finds that either of these solutions will completely dissolve 

 chitin in a short time with the aid of heat. For this purpose the 

 commercial solution should be taken concentrated and boiling. 



If solutions diluted with 4 to 6 volumes of water be taken, and 

 chitinous structures be macerated in them for twenty-four hours 

 or more, according to size, the chitin is not dissolved, but becomes 

 transparent, soft and permeable to staining fluids, aqueous as well 

 as alcoholic. The most delicate structures, such as nerve- endings, 

 are stated not to be injured by the treatment. The method is 

 applicable to Nematodes and their ova, and also to the removal of 

 the albumen from ova of Amphibia, etc. 



