32 



This solution is filtered off from the flocculent precipitate, 

 formed by the addition of the alcohol. It is evaporated 

 nearly to dryness, and the dissolved matter again taken 

 up by water ; the aqueous solution so obtained reduces 

 Fehling's solution. This series of reactions is charac- 

 teristic of mucine and chondrine, since glycogen or other 

 carbohydrates capable of yielding sugar on treatment with 

 dilute acid, and consequently reducing Fehling's solution, 

 are absent. 



Further the addition of crystals of magnesium sulphate 

 in excess to the aqueous solution of the styles, gives an 

 abundant precipitate which contains practically all the 

 proteid matter present in the solution. This behaviour 

 with magnesium sulphate, which agrees with that of a 

 globulin, and the reaction with dilute acid, indicate the 

 nature of the substance. It is allied to, but apparently 

 not identical with mucine. 



Leaving out of account the older views concerning the 

 function of the crystalline style, such as that of von 

 Heide, that it was an accessory genital organ, or that it 

 was a skeletal structure (Cams and Garner), or the 

 representative of the radula of the Glossophora, and 

 consequently a masticatory organ (Meckel), only two 

 hypotheses as to its nature seem to survive modern 

 investigation. Hazay* as the result of a series of observa- 

 tions and experiments, concluded that it represented a 

 store of reserve food material, resulting from the meta- 

 morphosed excess of food matters taken in during the warm 

 season, and lodged in the pyloric caecum to be utilized by 

 the animal during periods of hibernation. Practically the 

 same conclusion was arrived at by Haselofft from a series 



* Die Mollusken-Fauna von Budapest II. Biologischen Theil. Cassel, 1881. 

 t Ueber den Krystallstiel der Muscheln nach Untersuchungen verschiedener 

 Aiten der Kielcr Buclit. Osterode, 1888. 



