326 



Dr. A. B. Griffiths. 



[June 21, 



towards the aboral side, the stomach forms the well-known penta- 

 gonal "pyloric sac." The pyloric sac gives off five radial ducts, each 

 of which divides into two tubules bearing a number of lateral 

 follicles, whose secretions are poured into the pyloric sac and 

 intestine. The author has proved the nature of their secretion to be 

 similar to that of the pancreatic fluid of the Vertebrata (' Edinburgh, 

 Roy. Soc. Proc.,' No. 125, p. 120). Recently, the secretion found in 

 the five pouches of the stomach (of Uraster) has been submitted to a 

 careful chemical and microscopical examination. "With a quantity of 

 the secretion, obtained from a large number of starfishes, the follow- 

 ing experiments were performed : — 



1. The clear liquid from these sacs was treated with a hot dilute 

 solution of sodium hydrate. On the addition of pure hydrochloric 

 acid, a slight flaky precipitate was obtained, after standing seven and 

 a half hours. These flakes when examined beneath the microscope 

 (^-in. obj.) were seen to consist of various crystalline forms, the 

 predominant forms being those of the rhomb. On treating the 

 secretion alone with alcohol rhombic crystals are deposited, which 

 are soluble in water. When these crystals are treated with nitric 

 acid and then gently heated with ammonia, reddish-purple murexide 

 is obtained, crystallised in microscopic prisms. 



2. Another method was used for testing the secretion. It (the 

 secretion) was boiled in distilled water and evaporated carefully to 

 dryness. The residue obtained was treated with absolute alcohol and 

 filtered. Boiling water was poured upon the residue, and to the 

 aqueous filtrate an excess of acetic acid was added. After standing 

 some hours, crystals of uric acid were deposited and easily recognised 

 by the chemico-microscopical tests mentioned above. 



The above alcoholic filtrate was tested for urea. First of all, the 

 alcoholic solution was diluted with distilled water, and boiled over a 

 water-bath until all the alcohol had vaporised. The warm aqueous 

 solution (A) remaining was now tested for urea, in the following 

 manner : — 



(a.) On the addition of a solution of mercuric nitrate to a portion 

 of the above solution, no white precipitate was obtained. 



(6.) To another portion of the solution (A), a solution of sodium 

 hypochlorite was added. No bubbles of nitrogen were dis- 

 engaged. 



(c.) No crystals of urea nitrate were formed in a small quantity of 

 the solution (A) [concentrated by evaporation] after the addition 

 of nitric acid. 



(d.) The distillation of a small quantity of the solution (A) with 

 pure sodium carbonate, in a chemically clean Wurtz's flask 

 attached t) a small Liebig's condenser, failed to produce in the 

 distillate any coloration with Nessler's reagent. 



