

1815.] Analysis of the Excrements of the Boa Constrictor. 415 



solution was added pure ammonia. A precipitate fell, which was 

 phosphate of lime. On adding carbonate of ammonia, there was 

 a slight precipitate of carbonate of lime. After this phosphate of 

 soda produced a very distinct crystalline precipitate, indicating the 

 presence of magnesia. The quantities of these were too small to 

 be weighed separately, but altogether their weight must have been 

 •16 gr. for 1-56 — 1-20 = -16. Now -lb" x 5 = -8, the quantity 

 of these substances in 100 parts, 



D. Lastly, the quantity of animal matter, independently of tlie 

 gric acid, destroyed by combustion, was estimated at 2'y4 per cent. 

 For 100 — yO-16 +17 + 3-45 + '95 + -8 = 2-94. 



Hence 100 parts of these excrements contained 



Uric acid 90-lG 



Potash 3-45 



Ammonia 1 70 



Sulphate of potash, with a trace of^ 



muriate of soda ? J 



Phosphate of lime ") 



Carbonate of lime > 'SO 



Magnesia J 



Animal matter, consisting of mucus ) ^,^., ' 

 and a little colouring matter. ... J 



100- 



Ohservations. — I. c. 2. Oxalate of ammonia will often throvr 

 down lime when in a state of union with animal matter, together 

 with the animal matter itself, when other tests will scarcely indicate 

 its presence. This may be verified by almost any secretion from a 

 mucous membrane, most of which contain lime united to an animal 

 matter. For this interesting observation 1 am indebted to Mr. 

 Wilson. The lime, tbereforc, in t!ic present instance, was pro- 

 bably in union as an aliment with an animal matter analogous to 

 mucus, and which was doubtless derived from the hitcrnal passages 

 of the animal. It was insoluble in a weak alkaline solution, and 

 hence could easily be separated by its nicani?. The acid also, as 

 before observed, took up a small quantity of a yellow colouring 

 matter. The quantity of these, however, as estimated above, was 

 j)ro!»ably a little too great, since a small portion of the uric acid was 

 doubtless removed by the repeated washings, which of course 

 caused these matters to appear more abundant than they really were. 



1. c. 3. It is extremely dilUeult to ascertain the quantity of 

 ammonia contained in a sui»stance. 1 had before observed that this 

 alkali was present, and the aliove mode occurred to me of esti- 

 mating its quantity. Ferhajjs it is not very far from the trurli, 

 thougli it can hardly l)e rtlied upon as indicating the exjict amount. 



II. — ,^. The alkaline matter present Wiis considered as jiofasli, 

 on account of the facility with which its sul)carboi)ate and acetate 

 attracted moisture from the air, and also from its precipitating 



1 



