452 



this gas, as proved by its smell and appropriate metallic tests. 

 In milder forms I have seen nausea, and an approach to 

 coma, with dilated pupil, and a feeble irregular pulse, as the 

 more prominent symptoms, from a like exposure to these 

 noxious vapours, and it is with these elementary and com- 

 pound essences that disinfectants and deodorising agents are 

 more especially designed to deal, when impregnating the air 

 and other bodies with their peculiar foetor. The gaseous 

 combinations of carbon operate according to their degree of 

 concentration or proportion of aerial admixture, in a manner 

 analogous to those already considered. But besides being 

 the products of the decomposition of organised substances 

 and the processes of vegetation, we have familiar instances 

 of their generation in crowded close chambers, and in the 

 ordinary combustion of fuel. It is no unusual thing in Dis- 

 pensary and Parochial practice for us to find rooms in which, 

 from the number of their inmates, the air is so foul, chiefly 

 from having been repeatedly respired, that the flame of a 

 candle affords too small a light to see the patient, if we our- 

 selves, coming out of the fresh air, can approach him without 

 being almost stifled in the attempt. 



The effects of an atmosphere which will so languidly sup- 

 port the combustion of a taper, will be readily conceived to 

 be irrespirable with impunity by man ; and accordingly within 

 the last twelve months, at Halifax, we have had an instance 

 of one common lodging-house of two rooms having had sixty 

 sick inmates in the course of sixteen weeks. The head-aches 

 and giddiness frequently experienced from evening meetings, 

 when large numbers of people assemble in limited spaces, 

 arise from the same cause, together with the illumination, 

 which, in neglect of ventilation or any provision for the 

 renewal of the air within, rapidly converts portions of the 

 oxygen present into carbonic acid and oxide, attended by an 

 evolution of carburetted hydrogen and traces of hydro- 



