I 



REPORT ON THE LAWS OF COXTAGIOX. 81 



disengaging fomites, just as odours lurk unperceived in a garment 

 till the wearer enters a warm apartment. It is consistent with this 

 opinion, that clothes, which have been in contact with persons 

 suffering under typhus, sometimes infect those who wash them in 

 hot water. 4. The distance from the source of contagious effluvia, 

 at which porous bodies exert their absorbent power, is undeter- 

 mined. There is probably a distance at which their elasticity 

 may be so increased by dilution, as to be more than equivalent 

 to the absorbent power of the solid. The more highly the atmo- 

 sphere surrounding the sick is charged with contagious effluvia, 

 the more abundantly, may it be expected, that those effluvia will 

 be absorbed by solids. 5. The colours of porous bodies have been 

 shown, by the experiments of Dr. Stark, to exert a decided influ- 

 ence over their absorption of odours, the dark colours being most 

 efficient. He has suggested, therefore, by a fair analogy, that 

 colour may modify also the absorption of contagious effluvia*. 



XXV. In several well authenticated instances, persons convey- 

 ing fomites with injurious and even fatal effects to others, havr 

 themselves escaped infection. Prisoners discharged in theie 

 usual health from Newgate, at the time when that jail was the 

 seat of a contagious fever, have infected the keepers of shops and 

 public-houses in the neighbourhoodf. The same consequences 

 followed also the liberation of debtors from the jail at Gloucester. 

 In the memorable instance, too, already cited, the criminals who, 

 by the fomites lurking in their clothes, spread so fatal a pesti- 

 lence through the court of assize, were in their ordinary state 

 of health. Previous ablution of their bodies, and the putting on 

 clean and uninfected clothing, would doubtless have prevented 

 that extensive disaster. 



XXVI. Of contagious diseases, some attack the same individual 

 repeatedly : such are siphilis, typhus, and the plague. The last- 

 mentioned, however, rarely attacks twice during one season ; for 

 out of 4400 cases. Dr. Russell observed reinfection to happen 

 within that interval in 28 only J. Other contagious maladis, 

 such as smallpox, cowpox, measles, hooping-cough, and scarla- 

 tina, especially the first four, occasion some change in the human 

 body, which, in a great majority of instances, secures it during 

 life from a return of the same disorder. Smallpox and cowpox 

 act as safeguards against each other ; or when (failing this) the 

 one occurs in a person who has passed through the other, the 



* Philosophical Transactions, 1832. 



t Proceedings of the Board of Health at Manchester, p. 89— -100. Clark's 

 Collection of Papers, p. 10. 



I Russell On the Plague, pp. 190, 305. 

 1834. G 



