158 ; NATURE AND LIFE. 
tions with the fluids that moisten them, we find that they 
give rise to an infinite number of pairs constantly evolving 
electricity. The blood of the arteries with that of the 
veins forms a pair, having an electro-motive power of 0.57, 
that of a pair with nitric acid being 100. Becquerel ex- 
plains, by the intervention of these currents, many physio- 
logical phenomena hitherto imperfectly understood. Grant- 
ing the reality of such actions, yet it must be acknowledged 
that the general doctrine which combines them each with 
the other, and links the whole together with the various 
modes of action of the organism, is far from being clear 
and precise. We need to know how these currents are 
distributed and circulate, what lines and courses they fol- 
low. It is now time for experimental physiology to at- 
tack these difficult problems, the solution of which is abso- 
lutely necessary for accurate knowledge of vital determi- 
nations, that is, for the computation and the estimate of 
those various factors which are terms in all the equations 
of organic movement. 
Vegetables, too, develop electricity. Pouillet has 
clearly demonstrated that vegetation throws it off. Other 
physicists, particularly Becquerel, have proved the exist- 
ence of currents in the fruits, stems, roots, and leaves of 
plants. Becquerel took a branch of young poplar full of 
sap, introduced a platinum wire into the wood and another 
into the bark, and brought the two ends of the conductors 
together in a galyanoscope—the needle at once showed the 
passage of a current. Buff has lately made experiments, 
taking care not to injure the organs. Two vessels contain- 
ing mercury received platinum wires; over the mercury 
stood water containing the vegetables to be examined as to 
their electric condition. Taking the leaves and roots, Buff 
proved a current passing through the plant from the roots 
to the leaves; in a branch severed from the stem the cur- 
rent passed toward the leaves, too. To sum up, the exist- 


