On the Heat Production Associated with Muscular Work. 311 



They hold that the successive restorations of colour are due to fresh 

 supplies of chromogen being produced by the plant under the influence of the 

 hot water, and that each fresh amount is then oxidised to anthocyanin. 



We suggest that these phenomena are explained by the fact that though 

 a certain amount of pigment diffuses out into the water, a large proportion 

 of that which was origiually present is retained by the coagulated proteins of 

 the petals, of course in the colourless state. It is the successive liberation 

 of fractions of this retained pigment that accounts for the fresh production 

 of colour in hot water, and not a new formation of chromogen. 



On the Heat Production Associated with Muscular Work* 

 By E. T. Glazebrook, M.A., F.E.S., and D. W. Dye, B.Sc 



(Received December 1, 1913, — Eead January 22, 1914.) 



On reading Prof. Macdonald's paper it appeared that it might be interesting 

 to see if his results connecting the heat production and muscular work could 

 be expressed graphically or by means of some simple formula. The tables 

 in his paper give the heat production in calories per hour of a number of 

 individuals when doing a carefully measured amount of mechanical work on 

 a kind of treadmill or cycle. This amount of work is kept constant for each 

 group of observations in the paper. Table I gives his average results. 



Table I. 





Mechanical 

 ■work. 



Heat production. 



From observation. 



From formula. 



Group A 



13 



182 



179 



B 



19 



199 



202 



C 



43 



297 



296 



D 



56 



346 



347 



On plotting these as is done in fig. 1, it is cbar that the points lie very 

 approximately on a straight line, and it is easily seen that the equation to 

 this line may be written 



W 



H = 128 + 7 -^-„; (1) 



0-256' 



* A Note on Prof. J. S. Macdonald's paper, supra, p. 96. 



