Observations on South American and African Guano, 298 



As regards the American guano, the results of this coarse 

 analysis do not disagree with those of the more minute one of 

 Volckel, excepting in one particular ; he obtained 7 per cent, 

 of oxalate of lime, a salt which certainly did not exist in the 

 specimen which I examined ; and this I say, after having care- 

 fully sought for it. 



Comparing the constituents as they are placed side by side 

 of the American and African guano, the chief difference is seen 

 to be, that while the American kind contains a large propor- 

 tion of lithate or urate of ammonia, the African kind is totally 

 destitute of it. This I little expected, considering its origin, 

 the excrement of birds, their faeces and urine, the latter of 

 which commonly consists chiefly of lithate of ammonia. The 

 obvious explanation of the circumstance is, that the lithic acid, 

 which formed a part of the urine, has in a long period of time 

 suffered decomposition, and has given rise to oxalate of am- 

 monia. And, that this guano is very old, was indicated by 

 the partially decomposed state of some feathers, not excepting 

 the quills, which were included in it. I have said, that the 

 African guano is totally destitute of lithic acid ; and I believe 

 I am warranted in coming to this conclusion, having carefully 

 sought for it in vain. It may be mentioned that search also 

 was made in both kinds of guano for urea, but without well- 

 marked success. The brown animal matter, soluble in water, 

 yielded a small portion to alcohol, which had some of the pro- 

 perties of urea, and formed a compound with nitric acid, but 

 less distinctly crystalline than the nitrate of urea. 



On account of the origin of guano, that already referred to, 

 and the questions involved in the difference as to composition 

 which exists, or is supposed to exist, between it and the matter 

 from which it is derived, it appeared to me desirable to examine 

 with care the excrements of birds, and especially the urinary 

 portion, — thinking it not improbable, that besides lithate 

 of ammonia, [which it would appear, as far as experiment has 

 hitherto gone, is the principal constituent of the urine of birds, 

 whatever their food may be,] oxalate of ammonia might form 

 also a part. 



The specimens which I have hitherto examined have been 

 chiefly the following, viz., from the common goose, after feed- 



