52 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
(d) An enzyme probably produces its effect by causing alterations in chemical 
potential, and as a result can not only vary the velocity of a reaction, but can also 
start it or leave it at rest at various stages ; and, provided the amount of energy 
transference from osmotic to chemical energy is not great, may cause a considerable 
amount of synthesis and a variable point of equilibrium. 
