INFLUENZA IN HORSES. 



229 



or moisture, aud any assumed importauce' of this excess will be de- 

 stroyed by a refereuce to the Ibllowiug table giving the relative humidity 

 of the air at other places, where influenza did not appear during Sep- 

 tember, 1872. For part of this table, and for other facts in connection 

 with the weather, I am indebted to Brigadier-General Myers, Chief Offi- 

 cer of the Signal-Service, who kindly furnished the monthly meteorolo- 

 gical reports : 



Eelative hwmidUy per cent, for Scj)tember, 1872. 



The barometer had a low average for September, 1872, at Toronto — 

 29.5937, against 29.7200 of the same month in 1871. Its range, too, was 

 less, 0.728, against 0.799 in September, 1871. The average heights of 

 the barometer, at Toronto, in June, July, and August, 1871, were re- 

 spectively 29.5431, 29.5552, and 29.5780. 



Ozone. — It has been strongly contended that this agent is in excess in 

 the atmosphere during epidemics of influenza. Since Shouleim placed 

 a rabbit for an hour in an atmosphere artificially charged with ozone, 

 and found a resulting inflammation of the mucous membranes, and death 

 of the subject a few hours later, tlie potency of this agent in causing 

 influenza has been largely assumed. Additional weight was given to 

 the theory by the observations of Boeckel, of Strasburg, who found 

 that an excess of ozone in the atmosphere, if associated with cold east 

 or northeast winds, or snow, was capable of iuducing inflammation of the 

 air-passages. Boeckel further found that when he compelled animals 

 to breathe strongly ozonized air, lobular pneumonia was produced, (Levy.) 

 But there is no evidence that the catarrhs and pneumonias thus pro- 

 duced were capable of extending and assuming the character of an epi- 

 demic. It is found, indeed, that ozone does not exist in an atmosphere 

 loaded with organic impurities, the product of putrid decomposition, or 

 of animal respiration. Berigny could find no indication of the presence 

 of ozone in the surgical, fever, and venereal wards of the military hos- 

 pital at VersaOles, though it was abundant in the court-yard of the 

 hospital. James found a great deficiency in the military hospital at 

 Sedan, as compared with the garden of the hospital. Boeckel found 

 it in abundance on the iilatform of the cathedral at Strasburg during 

 the prevalence of cholera in that city ; but he rarely found a trace in 

 the streets of the town. Ho further asserts, as the result of his ob- 

 servations, that in air charged with paludal emanations ozone is not 

 produced. He was moreover unable to develop ozone to any extent in 

 a cholera ward. 



But these are precisely the conditions in which influenza assumes its 

 greatest severity and shows the highest death-rate. In the large cities, 

 where the air contains an excess of carbonic acid, given oil" by tires and 

 animal lungs, and an abundance of organic matter, the products of 

 wash and decay in organized bodies, this is unquestionably the case. 

 And just in proportion to the squalor, the filth, tlie impurity, and the 

 absence of a i^roper hygiene, so does the affection prove more severe 



