72 REPORT — 1855. 



The result, as deduced from this table, which has been calculated approximately from 

 the barometric pressure and dry- and wet-bulb thermometer, is analogous to that 

 obtained by Dr. Prout in 1832, as the author was informed by himself. Correspond- 

 ing observations have been made at Greenwich by Mr. Glaisher, and the same con- 

 clusions arrived at; from which it would appear that this superior weight of a given 

 bulk of air was not a local phoenomenon, but was diffused to considerable distances. 

 The character distinguishing September 1S54 from the corresponding period in 

 1855, was the absence of any atmospheric action on ozone test-paper in the 

 former season, while during the present year the oxidizing influence of the air has 

 never been absent at St. Thomas's Hospital. During September 1854, however, 

 when no ozone could be detected in London, its action was sometimes faintly and 

 often very strongly marked at Lewisham, near Greenwich. Throughout the same 

 periods the air was exceedingly stagnant ; and it has since been observed by Mr. 

 Glaisher, and also at Vienna, that rapid atmospheric movement is pretty constantly 

 accompanied by an oxidizing condition of the air. With reference to the chemical 

 composition in the atmosphere of inhabited localities and of malarious districts, expe- 

 riments have usually been conducted on the constitution of the gases which enter 

 into the composition of the air. But the results seem to have thrown little light on 

 the possibility of the production, from such causes, of any disease characterized by a 

 regular sequence of symptoms. So far as our knowledge warrants, gases can either 

 act only as asphyxiating media by the exclusion of oxygen, or as slow or rapid poi- 

 sons. The cause capable of inducing a disease formed on a peculiar type, analogy 

 leads us to infer must be an organized condition, either in a solid form or in a finely 

 diffused or vaporific state. The fact observed, that in malarious atmospheres sulphuric 

 acid speedily becomes black, also points to the propriety of examining the air in such 

 situations, with the view of filtering from it solid or condensable matter. In the epi- 

 demic of 1849-50, the author examined the exterior air of an infected district with 

 this object in view, to the extent of many cubic feet ; but the result was comparatively 

 negative, and led to the inference that the examination of large masses of air could 

 alone hold oat any prospect of a successful issue. For this purpose air was passed 

 through carefully prepared distilled water, contained in Woulfe's bottles, by means of 

 a large aspirating apparatus of the capacity of 16 cubic feet, which was kept constantly 

 in action during the day for several months. Occasionally, freezing mixtures were 

 applied to portions of the apparatus, and a tube filled with pumice moistened with 

 sulphuric acid placed next the aspirator completed the series. A range of tubes con- 

 ducted the air from a cholera ward into the aspirator. The ward was 32 feet long, 

 20 feet wide, and 9 feet high. The air was drawn from the centre of the ward near 

 the ceiling ; and when the apartment was filled with cholera patients, the air, after 

 traversing several layers of distilled water, was speedily charred by the sulphuric acid, 

 previously depositing a variety of solids in all the Woulfe's bottles, which could even 

 be detected in some measure by the eye. The objects consisted of blue and red cotton 

 fibres from the dresses of the inmates, portions of hair, wool, fungi, sporules of fungi, 

 abundance of vibriones or lower forms of animal life, with particles of silica and dirt. 

 In this and all the experiments conducted on the air of closed apartments, the distilled 

 water was rendered strongly acid from the presence of sulphuric and sulphurous acids 

 derived from the products of gas and coal combustion. The distilled water employed 

 in these experiments was boiled for some time previous to being introduced into the 

 apparatus, and was divided into two portions; one part being placed in a stoppered 

 bottle beside the Woulfe's bottles through which the air was conducted, the sediment, 

 if any, being afterwards examined and compared with that resulting from the experi- 

 ment. When the ward was partially full, vegetable epiderm, vegetable cellular tissue, 

 fragments of wood, cotton, linen, vegetable hairs, a sponge spicula, minute fungi, 

 spiral vessels, sporules, spore cases, animal epithelium, oil-globules, and siliceous 

 particles were detected ; while vibriones were entirely absent, or at least mere traces 

 could be discriminated. This is an interesting result, since in the first case only 98'6 

 cubic feet were examined, and of the partially empty ward 240 cubic feet passed 

 through the apparatus. When the ward was empty, cotton fibres, wool, a trace of 

 fungus with carbonaceous and siliceous particles were alone discernible, the amount 

 of air examined being 304 cubic feet. The air external to the ward and in the im- 

 mediate neighbourhood afforded, from 560 cubic feet, one cotton fibre, one of wool, 

 a crystalline body (probably a sponge spicula), sporules, beautiful mycelia of fungi in 

 various stages of development, and some carbonaceous matter. The distilled water 



