98 THE POPULAR SCIENCE MONTHLY. 



same direction. They both get rid of waste, and with it of the 

 poisons in the system, which are depressing various organs. We 

 need not, therefore, be surprised when we are told by Sir D. Gal- 

 ton that after barracks were better ventilated the rations of the 

 men had to be increased ; or by " the pathetic story " of certain 

 seamstresses whose work-room was ventilated, and who then 

 begged that the old state of things might be restored, as their 

 appetites had increased beyond their earnings. Sir D. Galton 

 gives another experience, illustrating the depressive effect of 

 these poisons upon the functions of life. A New York medical 

 man rather cruelly shut up some flies without food, some in foul 

 air, others in pure air ; the pure air being constantly changed. 

 To his surprise, the flies in the pure air died first, these dying 

 from simple starvation ; while the flies in the foul air died from 

 poison, and with the tissue of their bodies unexhausted, indicat- 

 ing how the functions of life were carried on to the last where 

 oxygen was available, but had been slowed and depressed by 

 the presence of the poison, so that life was actually maintained 

 longer in the foul than in the pure air. To take one more ex- 

 ample. Parkes tells us (page 159) that it was found in the case of 

 miners that they required six thousand cubits of air introduced 

 per man per hour (this included the air necessary for horses and 

 lights) to be able to work at their best. When this quantity was 

 reduced to one third or one half, there was a great reduction in 

 their working energy. In other words, the poison within their 

 system being imperfectly oxidized, impaired their faculties.* 



We could wish that it were possible to write the whole of the 

 noble story of oxygen from a physiological point of view. It is a 

 double service that it performs for us. It not only, as we have 

 seen, neutralizes the deadly poisons resulting from waste, but it 

 provides the heat and energy, by the oxidizing or burning up of 

 this waste. All through animal life the consumption of oxygen, 

 serving this double purpose, is the measure of activity. Just as 

 reptiles and cold-blooded creatures consume small amounts of oxy- 

 gen and develop little activity, so birds and insects consume im- 



* We may also take the case of races living in hot and cold climates. In hot climates 

 we breathe a smaller quantity of oxygen (owing to the expansion of gases) than in cold 

 climates. Thus, taking two climates, one of 32 F. and the other of 80 F., we should in- 

 hale about 2,164 grains of oxygen per hour in the one climate (the cold), and only 1,971 

 in the other climate (the warm), or a difference of about nine per cent (Galton, Our 

 Ilomes, p. 498). This would in part account for the difference of energy that exists in 

 the races of hot and cold climates ; just as our own energy varies considerably on hot 

 days and keen frosty days, though we think some allowance ought to be made for the more 

 open-air life that would be led in the warm climate. The bearing of these facts upon 

 crowded rooms should be perceived. As the room gets hotter, not only are we breathing 

 more poison, but less oxygen, which is the only remedy for the poison. We are therefore 

 doubling the causes of evil. 



