by deposition of laminae about two large nuclei. Exterior smoothly tubercular.
2531. Uric acid and urate of ammonia. 2" 2'" by 1" 8'". Part of thick cortex of large stone. Structure, porous. Pale brown. Exterior tuberculated and grooved.
In the next eleven specimens the urate of ammonia is in larger proportion than in the last nine.
2532. Ur. ac. and urate of ammonia, Length, 2" 4'". Irregu- lar clump of a large, dark, reddish-brown stone. Frac- tured surface shows finely the fan-like radiation of its coarsely crystalline structure. Exterior tuberculated, and indented.
2533. Uric acid and urate of ammonia. 1" 7"' by 1" 3'". Pale; pinkish-white ; friable ; mortar-like ; oval.
2534. Ur. ac. and ur. of ammonia. I" 3"' by 1". Compressed ; ovoid. Centre of a reddish-ochre color. Outer portion, yellowish-fawn. Exterior smoothly granular. Both halves preserved.
2535. Uric acid and ur. of ammonia. 1" I" 1 by 1" 2"'. Irreg- ular, ovoid. Porous. Exterior tuberculated.
2536. Uric acid and urate of ammonia. 1" 3"' by 8'". Com- pressed, irregular, spheroid, with one surface deeply con- cave. Nucleus very porous. Cortex pale fawn, and smooth.
2537. Ur. ac. and ur. of ammonia. 10'". Compressed spheroid. Resembles much a nutmeg in color and structure. Exterior polished.
2538. Ur. ac. and ur. of ammonia. 8'" by 9'". Compressed spheroid. Nucleus, grayish- white. Outer portion, yellow- ish-fawn color ; and covered with flattened tubercles.
2539. Ur. ac. and ur. of ammonia. 9"' by 1'". Oblong, ovoid, and much resembling the last specimen.
2540. Ur. ac. and ur. of ammonia. 1" by 10'". Compressed, oval. Pale fawn color. Between the centre and cortex is seen a lamina presenting the nacreous lustre peculiar to this form of calculus.
2541. Ur. ac. and ur. of ammonia. 10"' by 9'". Spherical. Exterior friable, and mottled with faint pink.
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