463 



to the nervous system, their effect will be to diminish sus- 

 ceptibility to the absorption of malarious poison, and afford 

 purity and freshness to the chambers of the sick. In this 

 sense it is very possible they have some efficacy in the 

 secondary causes of epidemic disease, by lessening its inten- 

 sity and checking its spread when already generated. To 

 accomplish these objects is no mean enterprise, and it re- 

 mains for us very briefly and impartially to consider the 

 claims of each, and to compare their relative value for 

 some of the purposes assigned. 



Were testimony to govern our decision, the efficacy of 

 all these agents for all manner of ends upon organic and 

 inorganic matters would be sufficiently attested, and the 

 labour of selection superfluous ; for they severally enjoy 

 the sanction of names which, for weight of character and 

 professional eminence, have seldom been surpassed. On the 

 other hand, their introduction has, by some persons, very 

 unjustly been condemned. But so long as we have excava- 

 tions in back yards surmounted by high walls, the receptacles 

 of all kinds of decomposing filth and garbage, steeping the 

 ground itself with rottenness; so long as the cesspool sys- 

 tem and the consequent nuisance of periodical removals of 

 the night-soil is suffered to continue ; so long as streets are 

 built without reference to size, aspect, or inclination, and 

 houses erected upon ill constructed drains ; and so long as 

 the present defective sewerage, exhaling a malarious atmos- 

 phere, engenders fever and lowers the general standard of 

 the public health ; — so long, I apprehend, we shall view with 

 favour any means whereby the air may be purified, stench 

 mitigated, and further putrefaction arrested. 



I have had opportunities of repeated trials of nearly all 

 these agents, more especially in reference to their anti-bromic 

 or smell-destroying properties, not only separately but collec- 

 tively; for by comparison alone can we hope to arrive at a 



L L 2 



