218 THE WORK DONE. [BOOK i. 



equivalent to 3*21 meters of blood, this means that the left 

 ventricle is capable at its systole of lifting 180 grins. 3*21 m. high, 

 i. e. it does 578 gram-meters of work at each beat. Supposing the 

 heart to beat 72 times a minute, this would give for the day's 

 work of the left ventricle nearly 60 ; 000 kilogram-meters. Calcu- 

 lating the work of the right ventricle at one-fourth that of the 

 left, the work of the whole heart during the day would amount to 

 75,000 kilogram-meters, which is just about the amount of work 

 done in the ascent of Snowdon by a tolerably heavy man. 



