EFFECTS OF RESPIRATION OF A VITIATED ATMOSPHERE. 413 



previous preparation of their bodies for the reception and development of 

 the zymotic poison, being altogether overlooked. It is impossible, however, 

 for any one who carefully examines the evidence, to hesitate for a moment 

 iu the conclusion, that the fatality of Epidemics is almost invariably in pre- 

 cise proportion to the degree in which an impure atmosphere has been habit- 

 ually respired ; that an atmosphere loaded with putrescent miasmata may 

 afford a nidus wherein a zymotic poison undergoes a marked increase in 

 quantity and intensity, the putrescent exhalations from the lungs and skin 

 of the living subject being at least as effectual in furnishing such a "nidus," 

 as are the emanations from fecal discharges or from other decomposing mat- 

 ters ; that the habitual respiration of such an atmosphere tends to induce a 

 condition of the blood, which renders it peculiarly susceptible of perversion 

 by the introduction of zymotic poisons, and which favors their multiplica- 

 tion within the system j 1 and lastly, that by due attention to the various 

 means of promoting atmospheric purity, and especially by efficient ventila- 

 tion and sewerage, the rate of mortality may be enormously decreased, the 

 amount and severity of sickness lowered in at least an equal proportion, and 

 the fatality of Epidemics almost completely annihilated. The effects of 

 good drainage and water supply have been recently well exemplified in the 

 case of Salisbury : the average number of deaths for the eight years pre- 

 ceding the completion of the drainage in this town (excluding the Cholera 

 year) having been 27 in 1000, and for the same period since 21 iu 1000 ; an 

 actual reduction of almost one-fourth of the whole number. 2 And it cannot 

 be too strongly borne iu mind, that the efficacy of such preventive measures 

 has been most fully substantiated, in regard to many of the very diseases in 

 which the curative power of Medical treatment has seemed most doubtful ; 

 as for example, in Cholera and Malignant Fevers. The practical importance 

 of this subject may be estimated from the startling fact, which inquiries 

 prosecuted under the direction of the Board of Health have brought to 

 light; 3 viz., that the difference in the annual rates of mortality, between the 

 most healthy and the most unhealthy localities in England, amounting to no 

 less than 34 in 1000, is almost entirely due to Zymotic diseases, which might 

 be nearly (if not completely) exterminated by well-devised sanitary arrange- 

 ments. The lowest actual mortality is 11 per 1000, while the highest is 45 

 per 1000 ; and between these extremes, there is every intermediate degree of 

 range. But what may be termed the -inevitable mortality, arising from dis- 

 eases which would not be directly affected by Sanitary improvements is a 

 nearly constant quantity throughout ; namely, the 11 per 1000 of those dis- 

 tricts which are free from Zymotic disease. The average mortality of all 

 England, in ordinary years, is about 22 per 1000, or just double that to 

 which it might be reduced ; so that, taking the population of England and 



1 A careful consideration of the very satisfactory evidence which has been of late 

 years collected on this point, must (in the Author's opinion) satisfy any competent 

 and unprejudiced inquirer, that endemic Fevers, originating in local causes (marsh 

 miasmata and the like), and at first affecting those only who are exposed to such 

 causes, may find, by the crowding together of infected subjects, a nidus for develop- 

 ment within the Human system ; so that these diseases then become communicable 

 by human intercourse, although not so originally For a discussion of this subject, 

 see the Articles on Yellow Fever and the Fever of Boa Vista, in the Brit and For. 

 Mod -Chir. Rev., vols. i, ii, and iv. 



2 See Times, Oct. 24th, 1863. 



3 See Summary of Experience on Disease, and Comparative Rates of Mortality, 

 by William Lee, Superintending Inspector, 1801. Nearly similar numbers are to he 

 found in the Twenty-ninth Annual Report of the Registrar-General, 1868. Of 13 

 large towns, the mortality of Liverpool was the highest (42 per 1000) ; that of Bir- 

 mingham and Hull the lowest, 24 per 1000. 



