508 PHYSIOLOGY AT THE FARM. 



without work, but taking a little exercise, in fair condition, on 

 12 Ib. of hay and 5 Ib. of oats ; but if a good amount of work 

 is to be got out of it, the horse should get 14 Ib. of hay, 12 Ib. 

 oats, and 2 Ib. beans." Professor Playfair goes on to say these 

 diets, reduced as regards their flesh-formers, are as follows : 



Horse at rest, . . .29.2 oz. of flesh-formers. 



Horse at work, . .56.2 oz. 



Difference for work, . 27.0 oz. 



" The labour of a horse," he says, " is commonly reckoned 

 equal to that of between 7 and 8 men;' and as the work- 

 ing-food of a labourer is 5.5 - - 2.0 = 3.5, the proportion 

 3.5 : 27 : : 1 : x, in which x 7.7 leads to the same result ;" 

 that is to say, the difference between the amount of flesh- 

 formers in the food of a labourer at rest, and the flesh-formers 

 in the food of a labourer at work, = 3.5 oz., has the same 

 relation to the difference between the flesh-formers in the food 

 of the horse at rest and the flesh-formers in the food of the 

 horse at work, = 27 oz., as the labour of a man has to the 

 labour of a horse, or 1 : 7.7 that of a horse being taken as 

 between 7 and 8 times greater than that of a man. 



The daily labour of which a horse is capable is certainly 

 much more than seven times that amount of energy which 

 Professor Playfair adopts as what a man may continue to exert 

 every day throughout the year viz., the elevation of 792,000 

 Ib. to the height of one foot. And this is true notwithstanding 

 that we cannot but think the Professor has adopted too high a 

 standard of the daily effort of which a horse is capable. But 

 not to dwell on this matter, we think it will be useful to state 

 here an estimate of the whole energy which a horse can put 

 forth under the two dietaries given by Professor Dick, as drawn 

 from the entire quantity of carbon contained in each respec- 

 tively in contrast with corresponding estimates. In reference 



