1885.] Uric Acid Crystals from Astacus fluviatilis. 187 



0' Sullivan, Cornelius. 

 Perry, Professor John. 

 Pickard- Cambridge, Rev. Octa- 



vius, M.A. 

 Pogson, Norman, CLE. 

 Pritchard, Urban, M.D. 

 Pye-Smith, Philip H., M.D. 

 Ringer, Professor Sydney, M.D. 

 Rodwell, George F., F.R.A.S. 

 Sanders, Alfred, F.L.S. 

 Snelus, George James, F.C.S. 

 Stevenson, Thomas, M.D. 

 Tate, Professor Ralph, F.G.S. 



Tidy, Professor Charles Meymott, 

 M.B. 



Tonge, Morris, M.D. 



Tribe, Alfred, F.C.S. 



Ulrich, Professor George Henry 



Frederic, F.G.S. 

 Unwin, Professor W. Cawthorne, 



B.Sc. 



Vines, Sidney H., D.Sc. 

 Warington, Robert, F.C.S. 

 Wharton, William James Lloyd, 

 Captain R.N\ 



The following Papers were read : — 



I. " On the Extraction of Uric Acid Crystals from the Green 

 Gland of Astacus fluviatilis." By A. B. Griffiths, Ph.D., 

 F.C.S., Lecturer on Chemistry and Physics, Technical 

 College, Manchester. Communicated by Sir RICHARD 

 Owen, K.C.B., F.R.S., D.C.L. Received February 6, 1885. 



The so-called green glands of the fresh water crayfish lie in the 

 cavity of the head below the front part of the cardiac division of the 

 stomach. The openings of these organs are to be found at the base of 

 each antenna. The organ carefully dissected out of the head of a 

 freshly killed crayfish is seen to consist of two principal parts : an 

 uppermost one which is a transparent and delicate sac-like body filled 

 with a clear fluid, and an underlying portion of a green colour, 

 glandular in appearance, containing granular cells. 



In 1848 Professors Will and Gorup-Besanez (see "Miinchen 

 Gelehrte Anzeigen," No. 233, 1848) said that this organ probably 

 contained guanin, and from this supposition this green gland has been 

 considered as a secretory organ. 



The secretion of this gland is acid to litmus-paper, and on treating 

 the secretions obtained from a large number of green glands with hot 

 dilute sodium hydrate solution, and then adding hydrochloric acid, a 

 slight flaky precipitate was obtained, and on examining these flakes 

 under the microscope they were seen to consist of small crystals in 

 rhombic plates. On treating the secretion with alcohol, these rhombic 

 crystals are deposited ; they are soluble in boiling water. 



When these crystals are precipitated from the secretion and 

 moistened with dilute nitric acid, alloxanthine (C 8 H 4 N 4 7 ) is pro- 

 duced, and on heating this body gently with ammonia, reddish-purple 

 murexide, or the "ammonium purpurate " (C 8 H 4 (NH 4 )N 5 6 ) of Prout 



o 2 



