PLATE 8. — Crystals from Animal Secretions. 



Figure 



1 . Uric acid ; human, natural, a, rhombs, front view, b, side view ; c, d, striated ; 



e, rhombs with obtuse angles truncated ; /, twin crystals ; g, ditto ; A, hour- 

 glass crystals ; i, nucleated ditto j ky I, m, n, o (and lower h), aigrettes ; p, large 

 dumb-bell forms. 



2. Uric acid J human, natural. «, front, by side view. 



3. Uric acid, coloured artificially by murexide (these crystals should have been 



coloured pink instead of yellow). 



4. Uric acid, natural. «, front, 5, side view; c, aigrette. 



5. Uric acid, precipitated from solution in sulphuric acid by water. 



6. Uric acid, rhombs, slightly acted upon with potash, showing spurious nuclei. 



7. Uric acid, precipitated from gout- stones. 



8. Uric acid of Boa, artificially precipitated, a — dy from solution in sulphuric acid 



by water ; e — A, from solution in potash by muriatic acid. 



9. Uric acid, precipitated from the excrement of the tortoise. 



10. Uric acid, precipitated from the excrement of the clothes-moth. 



1 1 . Urate of soda and ammonia, a, spheres with nuclei and concentric rings, arti- 



ficial ; b, surface covered with radiating needles ; c, d, e, natural forms ; 

 fy gy artificial. 



12. Urate of soda. «, artificial, deposited on cooling of an aqueous solution; 



by natural, as composing the chalky matter around gouty joints. 



13. ttyby Urate of lime. 



14. ttyby Urate of magnesia. 



15. Uric acid, precipitated by an acid from human urine. 



