BAD AIR AND BAD HEALTH. 97 



production, the one having a ratio of 1 to 5, and the other of 1 to 

 5*1, but there is a difference in potential energy in the two rations 

 equivalent to over 2,411,000 kilogramrne-metres of work, or one 

 and a quarter horse-power in the day's rations. 



In two other rations for milk-production with nutritive ratios 

 of 1 to 5 and 1 to 5*1, the difference in potential energy would be 

 represented by 3,112,000 kilogramme-metres, or 1*6 horse-power 

 for the day's feed. 



There are likewise rations with exactly the same nutritive 

 ratio (1 to 5), prescribed for Jersey cows giving milk, in which 

 the difference in potential energy is equivalent to 1,123,600 kilo- 

 gramme-metres, or more than one half of a horse-power for the 

 day's feed. There are also rations for horses, with nutritive ratios 

 1 to 6, and 1 to 6"4, which have a difference in energy of 2,834,000 

 kilogramme-metres, or the equivalent of over one and a quarter 

 horse-power for the day. 



It is unnecessary to cite further instances of the obvious fal- 

 lacies in rations that have been formulated in accordance with a 

 theory which ignores the significance of energy in animal nutri- 

 tion. The facts already presented must be sufficient to show that 

 the law of the conservation of energy should be recognized as an 

 important factor in the nutrition and growth of both plants and 

 animals, and that it should receive due attention in planning and 

 conducting experiments for the promotion of agricultural science, 

 and in interpreting their results. In the development of a rational 

 system of farm economy the applications of this general law must 

 have a dominant influence in determining the most profitable and 

 consistent methods of practice. 







BAD AIR AND BAD HEALTH. 



Br HAEOLD WAGER and AUBEEON HEEBEET. 

 \_Conclu ded.~\ 



EXERCISE, as well as pure air, helps us in our constant strug- 

 gle against the poisons that we manufacture within ourselves. 

 It does this by driving the blood charged with oxygen, by means 

 of the pressure of the muscles called into play, more thoroughly 

 through the tissue (Foster, page 219) ; and thus it would quicken 

 the breaking down of dead tissue into its safe and final waste 

 products (water, carbonic acid, and urea), and shorten the pe- 

 riod during which the dead tissue was passing through various 

 dangerous forms which it temporarily assumes. From this fact 

 we may infer that the man of sedentary life, above all others, 

 requires pure air. 



In truth, pure air and exercise are equal forces acting in the 



VOL. XLI. 10 



