How to seeure them. ivj 



Another question that might naturally occur in considering 

 house sanitation is, What becomes of the sewer gas ? Sup- 

 posing there are 50,000 houses in Belfast with 50,000 pipes all 

 pouring out poisonous matter into the air. Would not the 

 whole of Belfast have been probably poisoned long ago if this 

 were not got rid of ? Does the air act upon it by oxidation, 

 possibly by means of that more active form of oxygen, ozone, 

 which the late Dr. Andrews found in certain quantities in the 

 wholesome air of the country, but to a much less degree in 

 town air. Is this deficiency in town air because the ozone is 

 used up in oxidizing organic effluvia .? If so the whblesome- 

 ness of country air may be due to its ozone. On the other 

 hand however, Dr. Andrews showed that ozone in larger quan- 

 tities is poisonous, and it is therefore difficult to know just 

 how much is good for us. However, I want to direct atten- 

 tion to the fact that if this aeration of sewer gas destroys its 

 poisonous quality, proper ventilation in our houses is of para- 

 mount importance ; and I would suggest a system of ventilation 

 difTerent to what we usually have in ordinary houses. At 

 present, ventilation, especially in winter, is really an accident 

 not intended by the architect, and depends chiefly upon the 

 action of the open fireplace with its chimney sucking air out of 

 the house and producing a partial vacuum in the house, thus 

 causing everything outside to try to flow in. Cold air dubbles 

 through chinks in wmdows, ground air rises through the floor, 

 and sewer gas is^^sucked in also where possible. Now, if we 

 could devise some means of pressing air into the house instead 

 of sucking it out, we should get rid of these difficulties. There 

 could be no drawing in of foul gases ; on the contrary these 

 would be driven out. It must be left to the engineer, I suppose, 

 to devise means for a system of ventilation under pressure, but 

 something analogous to the wind-sails or ventilating cowls on 

 ships, down which the wind blows into the interior of the 

 vessel, might be practicable. 



Mr. Edward Winnington — The instructive lecture to which 

 we have just listened has been spoken to by the medical pro- 



