454 



■which renders them almost irrespirable. Their properties, 

 however, will by-and-by claim a passing notice as disinfect- 

 ants, to which branch of the subject, without further preface, 

 I propose now to proceed. 



To dis-infect is, I apprehend, to deprive from the air 

 and other bodies certain known or unknown deleterious or 

 offensive qualities, commonly designated by the terms infec- 

 tion, malaria, miasma, matter of contagion, volatile effluvia, 

 mephitic emanations, and the like, which, founded upon 

 observations innumerable, are productive of disease when 

 communicated to the constitution of susceptible individuals. 

 In this sense of the word is conveyed a comprehensive but 

 not very precise signification. To anti-contagionize might 

 afford in one of these senses a more definite mode of ex- 

 pression, had the word admitted of a verbal form. The 

 wider meaning, of course, best suits the vendor of a dis- 

 infectant as a commercial article, being co-extensive with 

 contamination of every kind. The line of distinction, how- 

 ever, which I would at the outset lay down is, that deleterious 

 agencies may be in operation appreciable only by their effects, 

 as well as those which are manifestly discernible by the aid 

 of the sense of smell. Both these kinds of infecting essences 

 may be, and in towns usually are, associated in the origina- 

 tion and difi'usion of epidemic pestilence, the extent, type, 

 and character of which will be materially modified in degree 

 as well as form, by the condition as to purity of the imme- 

 diate surrounding atmosphere, and the previously existing 

 state of health and habit of body of those infected by it. 

 Hence the passage in the Registrar General's late quarterly 

 report, that a cleanly town, when visited by a devastating 

 plague, is somewhat in the position of a city securely built 

 of stone in the midst of a general conflagration ; and hence 

 to the like effect are the conclusions arrived at by the 

 metropolitan sanitary commission, as enunciated in their first 



