Disinfecting Powers of increased Temperatures. 27 



destructible nature of the Jbmites of scarlatina, to that of other 

 contagions, remains analogical; and that experiments are still 

 wanting to extend the proof to other known species. The 

 argument, however, in its nature cumulative, has acquired a 

 great increase of probability by the step which has been made, 

 in showing that the power of heat is not merely exerted over 

 cow-pock infection, but extends to the active and virulent 

 contagion of scarlatina. 



The circumstances, under which the experiments wei'e con- 

 ducted, render it, I think, demonstrable that the disinfecting 

 agency belongs to heat alone; for the receptacle, in which 

 the infected waistcoats were placed, having in every instance 

 been closed, change of air could have had no share in the 

 effect. The phaenomena, then, are reduced to their simplest 

 form ; and the results put us in possession of a disinfecting 

 agent, the most searching that nature affords ; — one that pe- 

 netrates into the inmost recesses of matter in all its various 

 states. As a disinfectant of articles which are capable of im- 

 bibing and retaining contagion, heat is greatly superior to the 

 vapours or gases used for the same purpose ; inasmuch as the 

 transmission of the latter may be stopped by a few folds of com- 

 pressed materials ; while heat, if time enough be allowed, finds 

 its way in spite of all obstacles. To avoid being misunder- 

 stood, I must however repeat, that it is to the destruction, by 

 heat, of contagion existing in substances technically called 

 " susceptible," that I limit the proposal : — for instance, to in- 

 fected clothing of every description ; to infected bedding and 

 bed-furniture of every kind that would be spoiled by washing ; 

 to trunks and other packages brought by travellers from in- 

 fected places ; and to merchandise, whenever it can be shown, 

 or rendered highly probable, that such merchandise has been 

 in the way of imbibing contagious matter*. 



This is not the fit occasion for obviating anticipated diffi- 

 culties, arising out of the consideration of practical details. 

 A few of these have been candidly stated to me, and have led 

 to actual trials, chiefly as respects time and labour, the results 

 of which have been satisfactory to the objectors themselves. 

 The remaining element of calculation, the expense of aj^pa- 



• After taking great pains to obtain information, I have not been able 

 to satisfy myself whether any, and what amount of danger exists from the 

 presence of contagion in merchandise. There is one article, however, 

 wliich is more likely than any other to be a vehicle of infection, viz. old 

 rant, of which large cargoes are constantly imported into this country. 



Letters, which are often rendered almost illegible by fumigation, might 

 be disinfected in this way, if closed, not with sealing-wax, but with wafers. 

 Writing-paper, I find by experiment, begins to turn brown a little under 

 300°; but it still retains its texture, and the ink is not materially clianged. 



E 2 rntuf 



