On the urinary Organs and Secretions of the Amphibia. 331 
lecting, from three weeks to a month or six weeks. When the 
bulk of the masses is so considerable as to distend the part, they 
~ are expelled by an unusual exertion of the animal, most com- 
_monly in the act of devouring its food, which it tales periodi- 
cally, at intervals of from three to six weeks. The urine is 
voided occasionally, accompanied by, but never mixed with, 
feces, When expelled, it is commonly in a soft state, of a bu- 
tyraceous consistence, which it loses from exposure to the air, 
and becomes hard and like chalk in appearance. This change 
is produced, | believe, merely by the evaporation of moisture. 
The quantity of solid urine secreted by snakes is very great, more 
even than might be expected from the size of their kidneys; it 
is not unusual to see masses weighing three or four ounces, 
voided by large snakes. 
The chemical nature of this urine was such as I expected.to 
find it; I say expected, because before | left England, | was told 
by Dr. Prout, that he had examined the excrement of a serpent 
in London, and had ascertained that it was nearly pure uric 
acid; such have I found it here in every instance, in at least 
eight that I have tried it; and the properties of that fresh from 
the ureter were precisely the same as of that contained in the 
receptacle, or of that voided. Before the blow-pipe, it emitted 
strong ammouiacal fumes, consumed without flame, and afforded 
only a very minute quantity of ash, consisting chiefly of phos- 
" phate of lime and a fixed alkaline phosphate, and a little carbo- 
nate of lime: in muriatic acid it was insoluble; in warm dilute 
nitric acid it was soluble with effervescence ; and the solution 
evaporated, afforded the pink residue almost peculiar to uric acid; 
in an alkaline ley it was soluble, and the solution was precipi- 
tated by muriatic acid. These properties sufficiently prove that 
the nature of the urine of snakes is as above stated. Besides uric 
acid, I have not been able to detect any other ingredient, nor do 
I believe that the urine contains any other, with the exception 
of a little dilute mucus, with which it is mixed and lubricated. 
2. Of the urinary Organs and Urine of Lizards. 
I have examined the urinary organs of four different species of 
lizard, the gecko iguana, a large species resembling the iguana, 
“ealled by the natives kobbera-guion*, and the alligator. The 
shape of the kidney varies in different instances ; to each ureter 
there is a papilla, and the papille are situated in the receptacle 
itself; and in.no other respect have I been able to discover be- 
tween the urinary organs of these lizards and of snakes, any 
material difference. Neither does the urinary secretion of these 
four species, and of many other species that I have examined, 
* For an account of this animal, see Knox’s History of Ceylon. 
differ 
