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Royal Microscopical Society. 
character and became a tough pasty mass. A portion of this was 
incinerated on platinum foil, and the fused residue was dissolved in 
distilled water. It did not yield the least trace of chlorine, but 
consisted apparently only of soda with a little carbonate. It 
occurred to me that chlorine might have been sublimed with am- 
monia, and I now took some of the precipitate formed by mixing 
hot solutions of urate of soda and chloride of sodium. This was 
thrown on a filter, and washed thrice. A portion of this was in- 
cinerated ; the rest was then well washed and again incinerated. 
The first incineration of the possible double soda salt yielded 
free indications of chlorine. 
The salt was then compressed for some time between blotting 
paper, and was afterwards incinerated. There were again good 
indications of chlorine ; so that the spheres were possibly a combi- 
nation of urate of soda and chloride of sodium. But the combina- 
tion if it really existed was destroyed by prolonged washing with 
distilled water; the salt left yielding no chlorine reaction. 
As far as may be judged at the present stage of the inquiry, 
two forms at least must be added to the three forms of urate of 
soda already observed. And I am inclined to arrange the five 
forms thus obtained in the following order, according to their 
several degrees of departure from the colloidal or quasi-living state, 
to the crystalline or not-living state : 
1. Gelatinous colloid. 
2. Molecular urate. 
3. Spherules of first kind, soft, and tending after a time to 
crystallize. 
4. Needles. 
5. Spheroids of second kind ; composed, as I believe, of matter 
originally crystalline, but subdued by colloid crowd to colloid form. 
i. The gelatinous colloid form has been observed both in solutions 
containing only urate with uric acid, and in solutions of urate and 
chlorides or phosphates. It appears to correspond with the gela- 
tinous form in which uric acid is deposited from alkaline solutions 
after the addition of acids, and, like that gelatinous form, has an 
impulse to crystallization. The gelatinous form of uric acid is 
called a “ hydrate ” by Prout and others. I am disposed to call it 
simply the colloid form, leaving the question of any chemical dis- 
tinction between a colloid and a crystalline form, such as would 
consist in hydration or non-hydration, an open question : though 
as it seems to me the alterations of molecular arrangement must be 
larger and more comprehensive than hydrations. 
ii. The urate assumes the molecular form where as a crystalloid 
it should take the spherical. The molecules may be either small 
spheroids or small crystals. They show the mark of two several 
influences — the influence of a recognized colloid such as gelatin in 
