146 BULLETIN OF THE BUREAU OF FISHERIES. 



The composition and function of the crystalline style was studied by Haseloff (iSSS), 

 who found that alcohol causes it to become opaque and thinner. Nitric acid makes it 

 turn yellow, and dilute hydrochloric acid prevents it from decomposing. It dissolves 

 in ordinary water, but more readily in salt water. In 1 per cent acetic acid it dissolves 

 completely in from two to three minutes. Treated for some time with sulphuric acid 

 it takes on a violet color. Picric acid will precipitate a solution of crystalline style. 

 If the solution is first treated with acetic acid and then with potassium ferrocyanide, a 

 white flocculent precipitate is formed. From these reactions Haseloff concluded that 

 the crystalline style is composed of albuminous matter and is therefore a reserve food 

 material. This view is given additional support by the fact that if mussels are starved 

 the structure will disappear in a few days, after which, if plenty of food is again supplied, 

 the structure reappears. 



Many different functions have been ascribed to the crystalline style. Heide (1684) 

 and Cailliaud (1850) thought it was related to the reproductive organs. Meckel (1829) 

 took it for a tongue. Garner (1841) believed it had something to do with the swelling 

 up of the foot. Milne-Edwards (1859) ascribed to it the function of stirring up the food 

 during digestion. Vulpian (1869) found that it contained some crystals of calcium 

 oxalate and concluded from this fact that it must be connected with the urinary function. 

 Saba tier (1877) described it as functioning to grind up and press the food against the 

 intestinal wall. Krukenberg (1880) considered it as a pestle which forced the digested 

 food as closely as possible to the absorbing epithelium as it passed along. Hazay (1881) 

 and Haseloff (1888) considered it as a reserve food material, while Barrois (1890) 

 believed it served only in helping to transport the food becoming dissolved in the stomach 

 and surrounding the food mass with a slippery coat. He evidently considered it a sub- 

 stance similar to mucin and chondrin and therefore without any food value. 



The best researches on the origin and function of the crystalline style since that of 

 Haseloff (1888) have been made by Mitra (1901), who employed chemical methods, and 

 List (1902), whose plan was to feed india ink to the shellfish and observe its effects on the 

 organ. List found that the strong bristlelike cilia of the cavity in which the crystalline 

 style lies swept the india ink particles around the rod in continuous rotations which moved 

 gradually forward. When it was completely covered with ink, he was able to observe 

 that the anterior end was being gradually dissolved in the stomach while the posterior 

 end was being formed of new crystalline style substance free from india ink. Further- 

 more, the coating of ink which remained on the rod was in turn covered with a layer of 

 the crystalline style material. List therefore concluded that the crystalline style is 

 secreted in the direct intestine from the tall epithelium of the side walls and that it 

 gradually moves forward to the stomach by a rotating movement set up by ciliary 

 action. In the stomach it dissolves and, as List assumes, probably serves as a food 

 substance. 



The function of the crystalline style has been most satisfactorily demonstrated by 

 Mitra (1901), who worked with fresh-water mussels. His analyses gave the following 

 as the chemical composition of crystalline style: Water, 88 per cent (approximately); 

 globulin, 1 2 per cent ; salts, 1 per cent. The composition is similar to that of the pan- 

 creatic secretion of dogs and suggests that the crystalline style may function as a 

 digestive ferment. Further experiments gave strong support to this assumption, for 

 it was found that two styles if added to 30 minims of starch solution would completely 



