528 THE POPULAR SCIENCE MONTHLY. 



upon galvanic instruments, and can even excite contractions in otber 

 muscles. 



Independent of these nervous and muscular electric currents, other 

 sources of this fluid exist in the animal economy. Currents are pro- 

 duced between the outer and inner surfaces of the skin, in the blood, in 

 the secreting vessels in fine, almost throughout the whole organism. 

 The experiments, as delicate as original, to which Becquerel has for 

 several years devoted all the activity of his green old age, authorizes 

 him now to assert the preponderance of electro-capillary phenomena in 

 animal life. According to this accomplished physicist, two solutions 

 of different nature, both conductors of electricity, separated by a mem- 

 brane or a capillary space, compose an electro-chemic circuit ; and, if 

 we reflect on the anatomical elements of the various tissues, cells, 

 tubes, globules, etc., in their connections with the fluids that moisten 

 them, we find that they give rise to an infinite number of pairs con- 

 stantly 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 explains, by the interven- 

 tion of these currents, many physiological phenomena hitherto imper- 

 fectly understood. Granting 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 follow. It is now time for experimental physi- 

 ology to attack these difficult problems, the solution of which is abso- 

 lutely necessary for accurate knowledge of vital determinations, 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 demon- 

 strated that vegetation throws it off. Other physicists, particularly 

 Becquerel, have proved the existence of currents in the fruits, stems, 

 roots, and leaves of plants. Becquerel took a branch of young pop- 

 lar 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 galvanoscope the needle at once showed the passage of a current. 

 Buff has lately made experiments, taking care not to injure the organs. 

 Two vessels containing mercury receive platinum wires; over the mer- 

 cury stood water containing the vegetables to be examined as to their 

 electric condition. Taking the leaves and roots, Buff proved a cur- 

 rent passing through the plant from the roots to the leaves ; in a branch 

 severed from the stem the current passed toward the leaves, too. To 

 sum up, the existence of vital electricity is incontestable, though we 

 do not yet precisely understand the conditions of this internal excite- 

 ment, and know nothing of its true relations with the unity of physico* 

 chemical operations in the living organism. 



