1815.] Analysis of the Excrements of ihe Boa Constrictor. 413 



I have restricted myself to compare iodine with sulphur and cliloune, 

 we might find analogies, though less numerous indeed, between it 

 and phosphorus, and several other bodies ; but I thought it better to 

 compare it only with those bodies to which it bears the greatest 

 resemblance, and among which I conceive it ought to be classed. 1 

 have been led by this to show that sulphur possesses all the general 

 properties of chlorine, and that we ought in consequence to place it 

 among those bodies which form acids by combining with hydrogen. 



{To be continued.) 



Article II. 



Analysis of the Excrements of ihe Boa Constrictor. By Dr. Prout. 



The substance sent me as the excrements of the boa constrictor 

 was solid, of a white colour inclining to yellow. Fracture earthy. 

 When rubbed on a hard surface it left a white mark like chalk. 

 Its feel, however, was rather more dry and harsh than that of 

 chalk, and it was more friable than that sul)stance. Smell faint 

 and mawkish. Sp. gr. 1385. 



I. — A. After making a few general experiments to ascertain 

 its nature and composition, 50 grains, well dried and in a state of 

 fine powder, were digested for 24 hours in dilute muriatic acid ; 

 the mixture being occasionally, during that time, gently heated 

 and well shaken. On adding the muriatic acid no effervescence 

 was perceived. The acid was then poured otF, and in order to re- 

 move the whole of it, the substance was repeatedly well washed 

 with distilled water, which washings were added to the acid. It 

 was now carefully dried and weighed, and was found to have lost 

 4*92 grs., which, of course, were taken up by the muriatic acid, 

 and remained in solution in it. 



B. On the substance which had been left undissolved by the 

 acid, and which had become of a bluish tinge, a solution of pure 

 potash was poured, which, on the application of heat, completely 

 dissolved it, forming a solution transparent and nearly colourless. 

 To this solution, while still warm, was added muriatic acid in ex- 

 cess, which occasioned a copious white precipitate in the state of 

 very minute but distinct grains, which, alter having been well 

 washed, was collected and dried. 'J'he following were its pro- 

 perties. It existed, as before stated, under the form of very 

 minute grains of a beautiful bluish white pearly ;ij)pearance. No 

 imcll. Nearly insipid. Very sparingly soluble in cold water ; but 

 rather more soluble in warm, and its solution faintly reddened lit- 

 mus. lns()lui)le in alcohol. It combined with all the alkalies, 

 earths, &c , forming compotmds very little soluble in water. 

 When nitric acid was poured upon it and heat applied, it was en- 



