42 Prof. TyndalPs Notes on Scientific History, 



the raising of 303000 lbs. 1 foot high =134143 thermal units 



{15*67 grins. 1 v i 

 oko i fof carbon. 



2o24 grs. J 



47. Assuming the weight of the whole heart to be 500 

 grammes, and deducting from this 77, per cent, of water, we 

 have remaining 115 grammes of dry combustible material. 

 Assuming this material to be equal to that of pure carbon, it 

 would follow that the entire organ, if it had to furnish the 

 matter necessary to its action, would be oxidized in eight days. 

 Taking the weight of the two ventricles alone as 202 grammes, 

 under the same conditions the complete combustion of this 

 muscular tissue would be effected in 3-g- days. 



VIII. 



48. This partial resume of half of Mayer's second memoir is 

 now ended. It embraces only the first 56 pages of an essay which 

 contains 112 pages. Mayer began, as has been stated, with the 

 question of vital dynamics. The observation which led to his 

 scientific labours was made on a patient at Java in 1840, and 

 in 1842 he published his first paper. He informs us that he 

 had put it briefly together to secure himself against casual- 

 ties*; and having done this, he continued his inquiries, and in 

 1845 published the memoir from which the foregoing extracts 

 are taken. He did this in the intervals of a laborious profession, 

 " ohne aussere Ermunterung," as he himself touchingly observes. 

 The full translation of the essay can alone give an adequate idea 

 of the research which it implies. Mayer probably had not the 

 means of making experiments himself, but he ransacked the 

 records of experimental science for his data, and thus conferred 

 upon his writings a strength which mere speculation can never 

 possess. From the extracts which I have given, the reader may 

 infer his strong desire for quantitative accuracy, the clearness of 

 his insight, and the firmness of his grasp. Regarding the recog- 

 nition which will be ultimately accorded to Dr. Mayer, a shade 

 of trouble or of doubt has never crossed my mind. Individuals 

 may seek to pull him down, but their efforts will be unavailing 

 as long as such evidence of his genius exists, and as long as the 

 general mind of humanity is influenced by considerations of 

 justice and of truth j\ 



* Phil. Mag. vol. xxv. p. 501. 



t The paucity of facts in Mayer's time has been urged as if it were a 

 reproach to him, but it ought to be remembered that the quantity of fact 

 necessary to a generalization is different for different minds. " A word to 

 the wise is sufficient for them," and a single fact in some minds bears fruit 

 that a hundred cannot produce in others. Mayer's data were compara- 

 tively scanty, but his genius went far to supply the lack of experiment, by 



