«» the "EffeEls of Nitrous Favour. 397 



*' firft were not feized with the difeafe, whilft the inoculation 

 f< took the ufual effect when performed with the fecond." 



In the converfation which Dr. Rollo and myfelf had with 

 Dr. Smyth, aboat the different methods of deftroying conta- 

 gion, I gave it as my opinion, that the ox. muriatic acid, in 

 the form of gas, deferved the preference, for the following 

 feafons :— ift, From its being a permanently elaftic fluid, it 

 was much more diffufible than the vapour of nitrous acid — 

 and, 2ndly, from the facility with which it defbroyed the 

 contagion of fmall-pox in the mod concentrated Mate, I had 

 little doubt of its efficacy in eradicating contagions in gene- 

 tal. I then mentioned the experiments with fmall-pox mat- 

 ter, which are related in the firft edition of Dr. Rollo's Trea- 

 tife on Diabetes *. Row the Doctor could confonnd this gas 

 with the vapour of nitrous acid, with which at that time t 

 had made no trials, it is difficult to conceive ; but however this 

 may be, it is neceffary the miftake mould be corrected : for, 

 although it be poffible,and even probable, that nitrous vapour 

 may deftroy the contagion of fmall-pox, yet it mould never 

 be admitted as a fact, until proper and fatisfaftory experiments 1 

 have been made. In the fame converfation I mentioned the 

 method now employed at Woolwich for fumigating with the 

 fulphurbus acid, and which we foppofed had fome advan- 

 tages over that ufuaKy practifed. It confifts in mixing inti- 

 mately two or three parte of pulveriled fulphur with one of 

 nitre ; a certain quantity of this mixture, proportioned to the 

 fize of the apartment, is to be introduced into an iron pot, 



* Mr. Cruickfhuuk, in March 179;, took two portions of recent fjixll- 

 pox matter from the fame pcrfon, and c*pofcd one portion to this gas (the 

 tx.mur. acid gas) for a few minutes, and with it iro.ulat.d the left arrat 

 of three drummers, while the right arms were inoculated with fome cf the 

 other portion. The pun&ures of the left arms had no marks of inflamma- 

 tion, except what fimplc pun&urc produces, and they entirely difappeared 

 itt a few davs. But the right armo took on the variolous adtion, and in two 

 of the perfons there was a general eruption. This experiment I as been 

 ftnee repeated, and with the fame fu'eeef Rollo on the Dinliits Mt&itta, 

 Tol. i. p. 61. 



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