On Gravelhj and Cdculotis Concretions. 307 



The evaporated solution reddened the skin, and, after 

 sDmetime, deposited crystals of oxalic acid; as happens 

 m all concentrated nitrous solutions of calculi of the uric 

 acid kind. To another small quantity was added some 

 pure alkaline lixivium, which very soon took it up, became 

 coloured, sweetish, and deposited the usual silky crystal- 

 Jine sediment upon the addition of acetous acid. No doubt 

 therefore, could remain, as to its identity with that natu- 

 rally deposited. 



Arid here, though irrelevant to my present object, and 

 merely with a view to excite the attention of the faculty, 

 may I be permitted to ask, how it happens, that in the 

 very worst kinds of typhus fever there is very little dimi- 

 nution ot the secretion or excretion of the acidulous phos- 

 phate ot hme? as appears by the acidity of the urine, lime 

 water, and the quantum of precipitate afforded by the oxalic 

 acid 5 whilst a very considerable one of the uric acid takes 

 place, and continues so until nearly the termination of the 

 disease, when it begins gradually again to manifest itself; 

 nrst, by the usual tests only, but presently, upon the c.nsis 

 taking place, m such quantity ai to become insoluble; and 

 theretore quickly precipitates (with some additional mixture 

 ot calcareous phosphate and animal mucilaginous matter) 

 under the form of our critical sediment or de^sit > or are 

 we not here again to admire the wise ceconomy of the Au- 

 thor of nature, which, by keeping up the considerable and 

 necessary bony excretion of the system, prevents the dan- 

 gerous accumulation of it which must ensue from its re- 

 tention during the long protracted period of many fevers > 

 1 might here ofier some conjectures in explanation, but 

 u-ili reserve them for another place. 



Having already trespassed so much upon the indul.rcnce 

 of the academy, I shall here content myself with bnefly 

 staling, that, from the above experiments and observations, 

 we may presume to say acids of every kind are prejudicial 

 jnd give rise to the formation of gravelly and calculous af- 

 tections, by causing a separation and crystallization of the 

 inhic acid contents of the urine within the body ; not pre- 

 tending, however, to deny the existence of other causes in- 

 fierent in the system itself, occasionally productive of si- 

 milar effects, as has been already observed. 



I shall now proceed to the second part of this inquirv; 

 namely, how far, or in what manner, alkaline matters are 

 conducive to llio alleviation of these complaints. 



[To be continued ] 



J'^ INll. Letter 



