236 



Memoir on the Fumigation of Letters. 



[kpt'il i, 



The Jliiiiccnlh ami foiirteenfli expcri- 

 nif Ills appear to sanction theaiiswcrof 

 tlie junta to tlio questions of govern- 

 ment. Constdcrins: at all tiirics, that 

 t!io letters are rlrieii before delivering 

 lliem to tliose to- wlioni they are ad- 

 ilressed ; that; oirdrvirr;; tliem, there is 

 an evaporation, and that tliis evapora- 

 tion, or the va|)otn' of the vinegar, as 

 well as the oxygenated ninriatic gas, 

 could penetrate tli(! letter and toncli it 

 at ail points, I performed the following 

 experiments, in orrler to give greater 

 force to the opinion of the junta, or to 

 Refute it. 



Fifteenth experiment. — I immersed a 

 letter, (luring half a minute, in the vine- 

 gar, as in the thirteenth experiment. I 

 had enclosed in it a piece of paper, 

 tinctured witli the turnsol, like that of 

 the twclflii exi>criment; and I dried it, 

 afterwards, by suspending it over a 

 sand bath. On oi)ening the letter, I 

 observed that the vinegar had only 

 stained the edges of the ineisrons, 

 whence I drew tlie eonelusion, that the 

 vinegar, dining the immersion, had not 

 penetrated dec|)cr; 1 however remaiked, 

 that the blue paper had assumed a rose 

 "colour ; it may thence be concluded, 

 that the vapour of the vinegar ^ad 

 penetrated the It^ttcr during the drying",' 



Sixteenth'experimeut.^X repeated the 

 fifteenth experiment without niakingtlio 

 incisions in the letter, which was writ- 

 ten both on the outside and in the inside ; 

 anid I observed tliat the blue j>aper had 

 afso assumed tlie rose colour, and that 

 iho inscription of tlie address was rather 

 effaced; 



' SiveiiteentJi experi'meitt. — I repeated 

 the lifleenth experiment, closing the 

 letter herinctically, and without makiug 

 any incisions in it. I afterwards re- 

 marked, that tiie blue colour had 

 changed to a rose colour, but it was 

 It'ss \ivid than in the fifteenth and six- 

 leeiitii experiments. 



These three last experiments, on 

 ilcmonstrating that the letters immersed 

 in the vinegar, (principally making the 

 inc'isioiis in them previously,) and dry- 

 ing them afterwards by the heat of the 

 fire, arc penetrated and affected by the 

 vinegar, in a state 6f vapour, or by the 

 agent of tlie disinfection, demonstrate 

 also that tliey may be disinfected, at 

 least by this agent, without being 

 pj)ened. 



Tiie&e same experiments justify the 

 hncieiit practice of iMarscillcs, where, 

 jiccording to Papon, (lie letters were 



disinfected without openiiig; them, with 

 t!ic excejftion of those which were sus- 

 pected of containing materials suscepti- 

 ble of infection. Tliese letters were 

 sent to tlie hospital to be opened and 

 fumigated. This exception appears, 

 however, useless; and is, perhaps, actu- 

 ally so, because, when the vinegar pene- 

 trates tiie letters, it penetrates also the 

 objects of silk, wool, or otiier suscepti- 

 ble things whatever, which may be 

 enclosed in tliem. But, if the paper 

 thus passed through the vinegar re- 

 inaiiis, can it so happen, t!iatthesusce|)- 

 tible materials, after having been pene- 

 trated by the vapour of the vinegar, be 

 not also purified ? The negative to this 

 rjueslion will only appear strange to 

 those, who do not properly consider, 

 that there is not a more cogent reasoti 

 for supposing tliat the vinegar is an 

 antidolc against the contagion of the 

 plague, adiiering to silver, paper, &c. 

 iiian against that which adheres to other 

 susceptible substances, because one as 

 well as the other is nothing more than 

 llie recipient of the contagion which is 

 the same in all. It is not an objection 

 against what has just now been said, on 

 the diversity of the processes which are 

 employed for disinfecting the different 

 Suspected substahces. Tliis diversity 

 arises from the nature of the merchan- 

 dize, and not from that of the contagion; 

 and the reason for not passing them 

 through the vinegar, is to prevent any 

 injury accruing to them, and also 

 because there is not a sufficient abun- 

 dance of it to soak all the merchandize 

 iniported in one or two vessels. 



Eighteenth experiment. — On mixing 

 an eighth of nitre, and another of sul- 

 phuric aciil, I performed, during ten 

 minutes, the fumigation in the stove of 

 Beanme, on two letters infected with 

 cadaverous gas, as in the thirteenth 

 experiment. Each contained paper 

 tinctured with tiunsol, but one had no 

 incisions made in it ; on the contrary, it 

 was hermetically closed. On opening 

 them, T observed that they retained the 

 cadaverous gas, and that the clear 

 colour of the paper had not undergone 

 any sensible alteration. 



This experiment proves, that the dis- 

 infecting process of Smith is not suffi- 

 ciently proj>er fur the puiilication of 

 letters, when they are not opened. 



JS'ineteenth experiment, — I repeated 



the eighteenth experiment, effecting the 



fumigation on the letters according to 



the process recently practised at Mar* 



seiiles, 



