RESPIRATION 329 



gas. There seems to be no evidence of accidents in sewers from any 

 other gas than HgS or CO ; but many strange smells are en- 

 countered, and we were once much alarmed by chlorine coming 

 from a bleaching factory. 



Air of Ships. In the compartments of a ship air is specially 

 liable to become foul owing to the air-tight conditions which 

 often exist. In a double bottom compartment, for instance, the 

 whole of the oxygen may disappear, owing to rusting or to ab- 

 sorption of oxygen by drying paint. In an ordinary compartment 

 battened down the same thing may also occur owing to slow ab- 

 sorption of oxygen by articles of cargo, such as grain, wool, etc. 

 Accidents from this cause are not infrequent if men descend with- 

 out first testing the air with a lamp or giving time for ventilation 

 to occur. In coal bunkers fire damp may accumulate in the absence 

 of proper ventilation, or else the oxygen may fall very low. Coal 

 trimmers are occasionally also affected by what appears to be CO 

 poisoning due to small quantities of CO formed at ordinary 

 temperatures in the slow oxidation of coal, as described above. 



The ventilation of passenger and crew spaces on ships was very 

 defective, particularly in rough weather, until fan ventilation was 

 generally introduced. It was forgotten that the rooms in a ship 

 do not ventilate themselves naturally through walls and roof, as 

 a house ashore does. Owing to the close quarters, it is often diffi- 

 cult to ventilate the spaces in a ship properly without causing 

 intolerable draughts. In the mess decks of warships this is specially 

 difficult, as there are hammocks everywhere at night. The matter 

 was investigated recently by an Admiralty Committee of which 

 I was a member and a system introduced by which equal amounts 

 of air can be made to issue from a large number of louvres on the 

 sides of ventilating ducts. In this way the men are supplied with 

 an average of 50 cubic feet of air each per minute, without any 

 unpleasant draught impinging on any one. The temperature, and 

 particularly the wet-bulb temperature in warm weather, can also 

 be controlled very efficiently by this plan. With men perspiring 

 more or less from heat, and giving off perhaps fifty times as great 

 a volume of aqueous vapor as of CO2, very ample artificial venti- 

 lation is needed when no other means of ventilation is available. 



Gas Warfare. It would be out of place to attempt to discuss the 

 nature and mode of action of the various substances used in gas 

 warfare; but a certain number of facts of physiological interest 

 in connection with respiration may be fitly referred to here. 



The first serious gas attacks were made, as is well known, with 



