On the Function of the Blood in Muscular Work. 15 



than the fall when contact is broken. In some of Henry's ex- 

 periments this seems actually to have occurred. Thus, with 

 a single cell as electromotor, he found the shock at make 

 barely perceptible ; but when the battery was increased to thirty 

 cells, the shock became more powerful at make than at break. 

 And here I must bring this rather disjointed paper to a close. 



Terling Place, Withani, 

 June 1. 



II. On the Function of the Blood in Muscular Work. By W. H. 

 Broadbent, M.D., Lecturer on Physiology at St. Mary's 

 Hospital Medical School*. 



IN the Philosophical Magazine for May 1867 there is a paper 

 under the title given above by Mr. C. W. Heaton, Professor 

 of Chemistry at Charing-Cross Hospital, the purport of which is 

 to show that the oxidation which yields the force exerted by the 

 muscles is intravascular, or that muscular force is generated en- 

 tirely from the blood and within the blood-vessels. As this 

 communication is considered by some eminent physiologists to 

 have established the hypothesis that the blood itself is both the 

 source and the seat of all the chemical change by which force is 

 developed in the animal organism, it is desirable to examine 

 whether the considerations on which it is based are really so con- 

 clusive. 



The point in question is whether the oxidation which evolves 

 muscular force is intravascular or extravascular. The arguments 

 employed by Professor Heaton are as follows : — 



1. "If the oxidation of muscle is effected in the tissue itself, 

 it is clearly necessary to suppose either that the oxygen, upon 

 the stimulus of the motor nerves, leaves its combination in the 

 corpuscle, traverses the walls of the capillary in company with 

 the outgoing stream of nutrient fluid, and only enters into new 

 combinations when it has passed to some comparatively dis- 

 tant muscle-fibre, or else that the corpuscle itself liquefies and 

 passes out bodily through the thin membrane with its loosely 



combined oxygen Any oxygen which passes out into the 



tissues must obviously pass in solution in the exudate." 



2. The lymph collected from the tissues and again poured into 

 the blood may be taken as the measure of the exudate which 

 passes out of the capillaries into the structures ; and it is shown 

 by careful calculation, exaggerating both the amount of exudate 

 and the proportion of oxygen dissolvable in it, that the quantity 

 of oxygen which could thus be carried to the tissue is utterly 



* Communicated by the Author. 



