NATURE 



'Octobl:ii 



iyi2 



in cages tilted with small, ill-ventilated sleeping- 

 chambers, we have found that the temperature and 

 humidity of the air — not the percentage of carbon 

 dioxide or oxygen — determines whether the animals 

 stav inside the sleeping-room or come outside. When 

 the air is cold, they like to stay inside, even when the 

 carbon dioxide rises to 4 to 5 per cent, ot an atmo- 

 sphere. \Vhen the sleeping-chamber is made too hot 

 and moist they come outside. 



The sanitarian saj's it is necessary to keep the COu 

 below o"oi per cent., so that the organic poisons may 

 not collect to a harmful extent. The evil smell of 

 crowded rooms is accepted as unequivocal evidence of 

 the existence of such. He pays much attention to 

 this and little or none to the heat and moisture of the 

 air. The smell arises from the secretions of the skin, 

 soiled clothes, &c. The smell is only sensed by and 

 excites disgust in one who comes to it from the out- 

 side air. He who is inside and helps to make the 

 " fugg " is both wholly unaAvare of, and unaffected 

 by it. Fliigge points out, with justice, that while we 

 naturally avoid any smell that excites disgust and puts 

 us off our appetite, yet the offensive quality of the 

 smell does not prove its poisonous nature. For the 

 smell of the trade or food of one man may be horrible 

 and loathsome to another not used to such. 



The sight of a slaughterer and the smell of dead 

 meat may be loathly to the sensitive poet, but the 

 slaughterer is none the less healthy. The clang and 

 jar of an engineer's workshop may be unendurable 

 to a highly-strung artist or author, but the artificers 

 miss the stoppage of the noisy clatter. The stench of 

 glue-works, fried-fish shops, soap and bone-manure 

 works, middens, sewers, become as nothing to those 

 engaged in such, and the lives of the workers are in 

 no wise shortened by the stench they endure. The 

 nose ceases to respond to the uniformitv of the 

 impulse, aiid the stench clearl}' does not betoken in 

 any of these cases the existence of a chemical organic 

 poison. On descending into a sewer, after the first 

 ten minutes the nose ceases to smell the stench ; the 

 air therein is usually found to be far freer from bac- 

 teria than tlie air in a schoolroom or tenement. 



If we turn to foodstuffs we recognise tliat the smell 

 of alcohol and of .Stilton or Camembert cheese is hor- 

 rible to a child, while the smell of putrid fish — the 

 meal of the .Siberian native — excites no less disgust 

 in an epicure, who welcomes the cheese, .^mong the 

 hardiest and healthiest of men are the North Sea 

 fishermen, who sleep in the cabins of trawlers reeking 

 with fish and oil, and for the sake of warmth shut 

 themselves up until the lamp may go out from want 

 of oxygen. The stench of such surroundings may 

 effectually put the sensitive, untrained brain worker 

 oft" his appetite, but the robust health of the fisher- 

 man proves that this effect is nervous in origin, and 

 not due to a chemical organic poison in the air. 



Ventilation cannot get rid of the source of a smell, 

 while it may easily distribute the evil smell through 

 a house. ."Vs Pottenkofer says, if there is a dung- 

 heap in a room, it must be removed. It is no good 

 trying to blow away the smell. 



Fliigge and his school bring convincing evidence to 

 show that a stuffy atmosphere is stuffy owing to heat 

 stagnation, and that the smell has nothing to do with 

 the origin of the discomfort felt by those who endure 

 it. The inhabitants of reeking hovels in the country 

 do not suffer from chronic ill-health, unless want of 

 nourishment, open-air exercise, or sleep come into 

 play. Town workers who take no exercise in the 

 fresh air are pale, anaemic, listless. Sheltered by 

 houses they are far less exposed to winds, and live day 

 and night in a warm, confined atmosphere. 



The widespread belief in the presence of organic 

 poisons in the expired air is mainly based on the state- 



Ko. 2240, VOL. qol 



ments of Brown Sequard and D'Arsenval, statements 

 wholly unsubstantiated by the most trustworthy 

 workers in Europe and America. These statements 

 have done very great mischief to the cause of hygiene, 

 for they led ventilating engineers and the public to 

 seek after chemical purity, and neglect the attainment 

 of adequate coolness and movement of the air. It 

 was stated that the condensation water obtained from 

 expired air is poisonous when injected into animals. 

 The evidence on which this statement is based is not 

 only not worthy of credence but is absurd, e.g. con- 

 densation water has been injected into a mouse in a 

 quantity equivalent to injecting 5 kilogrammes into a 

 man weighing t>o kilogrammes. No proper controls 

 were carried out. It is recognised now that any dis- 

 tilled water contaminated by bacterial products may 

 have a toxic effect. Flack and I have for fourteen 

 weeks kept guinea-pigs and rats confined together in 

 a box and, poorly ventilated, so that they breathed 

 air containing 05 to 10 per cent, of CO,. The 

 guinea-pigs proved wholly free from anaphylactic 

 shock on mjecting rats' serum. Therefore they were 

 not sensitised by breathing the e.xhaled breath of the 

 rats for many weeks, and we are certain that no 

 foreign protein substance is absorbed in this way. It 

 has been proved by others, and by us, that animals so 

 confined do well so long as they are well fed and their 

 cages kept clean, light, cool, and dry. It is wholly 

 untrue that they are poisoned by breathing each other's 

 breath. The only danger arises from droplet con- 

 taarion in cases of infective disease. 



To study the relative effect of the temperature and 

 chemical puriiy of the atmosphere, 1 constructed a 

 small experimental chamber of wood fitted with large 

 glass observation windows and rendered airtight. 



On one side of the chamber were fi.xed two small 

 electric heaters, and a tin containing water was placed 

 on these in order to saturate the air with water 

 vapour. On another side of the chamber was placed 

 a large radiator through which cold water could be 

 circulated when required, so as to cool the chamber, 

 In the roof were fixed three electric fans, one big and 

 two small, by means of which the air of the chamber 

 could be stirred. The chamber held approximately 

 3 cm. of air. In one class of experiments we shut 

 within the chamber seven or eight students for about 

 half an hour, and observed the effect of the confined 

 atmosphere upon them. We kept them until the CO.. 

 reached \ to j per cent., and the oxygen had fallen to 

 17 to 16 per cent. The wet-bulb temperature rose 

 meanwhile to about 80° to 85° F., and the dry-bulb a 

 degree or two higher. The students went in chatting 

 and laughing, but by and by, as the temperature rose, 

 Ihev ceased to talk and their faces became flushed and 

 moist. To relieve the monotony of the experiment we 

 have watched them trying to liglit a cigarette, and. 

 puzzled bv their matches going out. borrowing others, 

 only in vain. They had not sensed the diminution of 

 oxygen, which fell below 17 per cent. Their breathing 

 was deepened by the high percentage of CO., but no 

 headache occurred in any of them from the short 

 exposure. Tlieir discomfort was relieved to an 

 asfonishing extent bv putting on the electric fans 

 placed in the roof. Whilst the air was kept stirred the 

 students were not affected by the oppressive atmo- 

 sphere. They begged for the fans to be put on when 

 the-- were cut off. The same old stale air containing 

 3 to 4 per cent. CO, and 16 to 17 per cent. O, was 

 wliirled, but the movement of the air gave relief, 

 because the air was So° to 8,° F. (wet bulb"), while 

 the air enmeshed in tlieir clothes in contact with their 

 skin was 08° to Qq° F. fwet bulb"). If we outside 

 breathed through a tube the air in the chamber we 

 felt none of the discomfort which was being experi- 

 enced by those shut up inside. Similarly, if one ot 



