554 PHYSIOLOGY AT THE FARM. 



ant on the admission of cold air upon the bodies of animals 

 kept in an artificially-heated atmosphere.* 



The use of oxen in the labours of the field is perhaps irre- 

 coverably obsolete in this island. There are a few places where 

 traces of this usage still may be met with. Nevertheless it is 

 proper to consider whether or not this ancient practice has any 

 advantage to recommend its revival. It is stated as a fact 

 that an ox, after having been employed constantly in field- 

 labour for six or seven years, may be fattened for the market, 

 so as to furnish flesh of a far superior quality to that afforded 

 by younger animals. It may throw some light on this point 

 to repeat what was referred to before in Professor Play fair's 

 comparison between the amount of labour and the amount 

 of food respectively in the horse and in the ox. The food of 

 the horse in flesh-formers is 56.5 oz., the food of the ox 

 in the same, 38.6 oz., while the labour of the horse in foot- 

 pounds is 12,400,000, and that of the ox in the same is 

 8,640,000. 



But 56.5 : S8.6 :: 12,400,000 : 8,471,506, so that the work 

 of the ox in foot-pounds is greater than the proportion of 

 his food as compared to that of the horse by 8,640,000 - 

 8,471,506 = 168,494 foot-pounds daily. 



Hence this point deserves the serious attention of economists 

 in agriculture. It is to be remembered that the respective 

 estimates of the work of the horse and of the ox here stated 

 are not speculative deductions, but figures actually ascertained 

 by the use of familiar facts. If it be asked, how it is psssible, 

 on the principle of " the conservation of energy," that more 

 external mechanical work can be performed by one animal than 

 by another in proportion to the respective amounts of flesh- 

 formers consumed ? the answer is, that there is always a waste 

 of energy in the working of a machine intended for a definite 



* See 'Journal of Agriculture,' Nov. 1866, p. 265. 



