*i)8 Eff'ectual Means of 



llimigate, by tliis method, the letters 

 "which are considered suspicious. 



Under these cireunistatices, I con- 

 sidered it necessary to throw a greater 

 light on the queolion by new experi- 

 ments; not only because (ho importance 

 of the case required it, but because the 

 conoUjsions which my learned colleagiies 

 had drawn from those experiments, and 

 their opinion, on opening the letters, did 

 not agree with my own. 



The letters not bcin.x all composed of 

 half a sheet of paper, like thai on which 

 the second experiment wai madCj and 

 as it might hapjien that fhcy contained 

 articles susceptible of infection, it was 

 necessary to observe, what wonid be tho 

 result in letters more toliiminous, and 

 particularly in those in which materials, 

 susi;eptible of the infection, were en- 

 closed, in order to convince myself 

 finally of the manner in which the chlo- 

 jrinc penetrated the letters. To resolve 

 these problems, I perfornrod the follow- 

 ing experiments in the laboratory of 

 tlie Mint, for which pnrpose Doctor 

 G, J. De iSeixas, snb-director of the 

 laboratory, furnished me with every 

 assi^ance. 



Third experiment. — I took two sheets 

 ofpaper, and, having folded them length- 

 ways, I sealed them with wafers in a 

 sheet of paper, and I made four tran*- 

 vers .1 incisions in Ihem, each an inch 

 long ; placing them obliquely in the 

 stove, I caused the chlorine to develope 

 itself underneath the grate, adding, at 

 tlie same time, one ounce of common 

 salt, two-eighths of manganese, four- 

 ibighths of water, and six-eighths of sul- 

 phuric ac'd. I suffered them to remain 

 in the stove for fifteen minutes, and 

 then breaking the seals, 1 conveyed them 

 into aaoliicr apartment, where Doc- 

 tor Seixas, myself, and a servant 

 of tlie laboratory, observed, that the 

 sliecls of paper smelt inwardly of tho 

 chlorine. 



Fourth experiment. — T put in an en- 

 velope three sheets of paper, folded in 

 two, and made three incisions in them 

 of an inch long; and, after having pro- 

 ceeded in the same manner as in the 

 former experiment, it was remarked, 

 that the paper smelt sufficiently strong 

 of the chlorine. 



The result of these experiments, and 

 the observation which 1 made, that tho 

 letters which had been fumigated pre- 

 served for many days the odour of the 

 chlorine, induced me to think, that tho 

 vhlorioe does ttot introduce itself iiito 



Fumigating Letters. [Dec. 1, 



the letters only by the incisions. To 

 ascertain this fact, the loUowing cxpe- 

 rimfut was made. 



Fijth experiment. — I repeated the 

 fourth expeiinient without making the 

 incisions in the letter, and, on examin- 

 ing it afterwards, it Mas found to smell 

 strongly of the chlorine; but, as in the 

 fifth experiment, t:ir chlorine might have 

 insiimated itself into the letter by the 

 openings of the envelope. 



Sixth experiment. — I repeated the 

 firth experiment, closing with the seal- 

 ing-wax all tlie opcniriK'sof the envelope 

 in such a manner, that the letter ap- 

 peared hermetically closed. It was ob- 

 sfr\"ed, that the odour of the chlorine 

 was perceptible in tlie paper, in a lcs» 

 degree, however, than in the letters in 

 which the incisions had been made. 



Severtk crperiment. — I repeated the 

 sixth experiment, by putting the letter 

 in two envelopes, both being hermeti- 

 cally closed. The result was the same, 

 and the odour was so d( termined, that 

 my colleague and friend Dr. Piaheiro, 

 in whoso presence I opened the letter 

 two davs after the experiment, and who 

 entertained great doubts of its eflieacy, 

 recognized the odour of the chlorine, 

 and confessed that it iKid penetrated the 

 paper. 



If the chlorine extends its anti-con- 

 tagious povver, even to the inlcctiou of 

 the piague, no doubt can be entertained 

 that letters may be fumigated, accord- 

 ing to the process of M, Morvcau, with- 

 out opening them, and without even 

 making incisions in them. It must, 

 nevertheless, be decided, how long the 

 fumigation ought (o continue, and un- 

 der what particular circumstances it 

 may be ailirmed, that the suspected 

 letters arc disinfected by this process. 



Eighth experiment. — In order to de- 

 tennino this essential point, according 

 to the example of M. Morveau, I put 

 six ounces of meat to piitrify in a 

 saucer; above the meat 1 suspended 

 cotton, silk, hemp, wool, the feathers 

 of the wing of the pea-hen, and a piece 

 of fur ; and I placed the whole in a 

 glass receiver, surmounted with a cork. 

 Tliis . apparatus was immersed in a 

 bason containing water, half an inch in 

 depth. When I had ascertained by 

 means of the cork that the meat smelt 

 sufliciently strong of putrefaction, I ex- 

 amined the materials above-mentioned, 

 and I recognized in all of them the bad 

 smell of the meat. This smell was, 

 however, stronger iti the fcatliors aitd 



