108 
Transactions of the 
II. — Studies in the Natural History of the Urates. 
By W. M. Obd, M.B. Lond., Senior Assistant-Physician to 
St. Thomas's Hospital. 
{Bead he/ore the Royal Microscopical Society, January 6, 1875.) 
Plate XOIV. 
I. Urate of 8oda. — Uric acid, combined in various proportions 
with soda, and probably, as the experiments now to be related in- 
dicate, with other substances, presents itself to observation in three 
forms at least as a pathological phenomenon. Urate of soda is 
crystalline in tophaceous concretions and in cartilage, spherical in 
certain somewhat rare conditions of the urine, amorphous in car- 
tilage, tophi, and urine. 
In a slice of the cartilage from a gouty great-toe joint the urate 
occurs in long needles usually bent, and pointed at both ends. 
These are sometimes scattered, sometimes in parallel bundles, some- 
times in radiating tufts, sometimes woven and matted irregularly. 
Dr. Garrod,* Dr. Koberts, Drs. Cornil and Eanvier, and others, 
have figured this form of deposit, and as it agrees with the form 
in which neutral urate is artificially deposited, also figured by 
Dr. KobertSjt Dr. Beale,J and Drs. Ultzmann and Hofmann,§ I do 
not propose here to put forward any fresh drawing of a so-well- 
recognized form. 
Mixed with the crystals, masses and clouds of fine granular 
matter having a brownish tint by transmitted light may be ob- 
served. These agree with the amorphous form of urate of soda, 
EXPLANATION OF PLATE XClV. i 
Fig. 1. — Urate of soda, deposited in liquor sodae. 
„ 4. — Biurate (?) of soda, in gelatin. 
„ .5. — Uric acid in gelatin. 
„ 6 a. — Urate of soda, with uric acid, in gelatin. 
„ 6 6.— Ditto. 
„ 6 c— Ditto. 
„ 9. — Uric acid and urate of soda, in water. 
„ 17. — Uric acid and urate of soda in presence of concentrated solution of 
chloride of sodium. 
„ 18. — Urate of soda and uric acid with concentrated solution of chloride of 
ammonium. 
„ 19. — Deposit from solution of urate of ammonia after rapid evaporation — 
a, first day ; 6, second day. 
„ 20. — Urate of soda in concentrated solution of chloride of sodium. 
„ 21. — Urate of soda in concentrated solution of chloride of potassium. 
* *Med. Chir. Trans./ vol. xiii., 1848, p. 97. 
t ' Urinary and Renal Diseases,' p. 71. 
X * Urinary Deposits,' pi. xviii., figs. 98 and 100. 
§ ' Atlas der Physiologischen und Pathologischen Harnsedimente,* Taf. viii. 
