■tipon Dr. Jameses Po<uuhr. Ill 



tlon {jradnnlly into dirtilled water, prcvioufly alkallzated by a 

 fufficient quantity of ammonia. A white and abundant pre- 

 cipitate will take place, which, well wafhed and dried, is the 

 fiibftitute I propofe for Dr. James's powder. 



The theorv of this precipitation is fo clear and fimple that 

 it docs not require any comment. It may be ufeful, how- 

 ever, to thofe who wifh to make this preparation, to remark, 

 that it is abfdhitely necellarv that the folution of phofphate 

 of lime and of oxide of antimony, in muriatic acid, fliould, 

 alter being well mixed, be poured if/lo the alkaline liquor, 

 in order to obtain a precipitate homogeneous throughout the 

 operation. For, f])()u!d the alkaline liquor be poured into the 

 acid folution, the water of the former would act upon the 

 entire mafs of oxide of anlimonv, while the alkali would pre- 

 cipitate the phofphate of lime only as it faturatcd the acid 

 which held that fait in folution: thus the precipitate woulJ 

 contain more antimonv in the beginning; and, towards the 

 end, the pholphate of lime would be predominant. For the 

 fame reafon, too, a pure alkali is preferable to its carbonate; 

 for the carbonic acid difengaged would retain in folution a 

 portion of phofphate of lime. 



Whether this compofition be a chemical combination oi: 

 a mixture, I will not take upon me to determine ; but, for 

 the reafons above mentioned, in fpeaking ot Dr. James's 

 powder, I belive it to be merely a very intimate mixture. At 

 all events, it muil be more homogeneous than any that caa 

 be prepared in the dry way. It is entirely foluble in every 

 acid that can diHolve either j)hoipliate of litiie or oxide of 

 antimony feparately; and, to have it confiantly and uniformly 

 the fame, no further addrefs in preparing it is required, ihaa 

 to avoid the crror^ f have mentioned. 



As, after fome medical trials of the powder, it was fug- 

 gefted to me, that it might be advantageous to render it 

 lomewhat ftronsrer, I prepared another portion, by taking .tv/o. 

 parts of oxide of antimony and but one of phofphate of lime, 

 and precipitating as above defcrlbed. The mediciiij power 

 was then confiderably iuereafd. 



Dr. James's powder is a medicine which. has been fo loiig 

 in ul'e, and is fo defervedly ranked among the mod valuable 

 we polTefs, that every attempt to render the procefs for.prepar- 

 ing it more fimple and more certain, mud be allowed to be of 



diiccd to ftste fully thcil- particulars, bccaufe, from the beneficial eflliStit 

 of this fait in the treatment of rachitis, as propofed by M. Bonliomnu, 

 {Ati/U4ks i/e Cbtwif, vol.xviii. p. 113,) it may bccomL of genfriil u<c. Thp 

 oxide of antimony. I obtained by precipitating, by wat'.-r, the cotnmoti 

 butter of antimony of the ftiops. '-'^ 



■ fome 



