538 
W. J. TORRAMCE. 
produced, and for the catalytic action accredited the peculiar 
fluid. 
The physiology of the brain and spinal cord were little un¬ 
derstood until the stimulation of nerves and nerve centres was 
instituted, electricity being chosen as the stimulating agent, on 
account of its cheapness, easy regulation, rapidity of action, ac¬ 
curacy, etc. By vivisection of frogs, turtles, rabbits and smaller 
animals, exposing crainal, spinal and nervous areas, such as the 
pneumogastric, sympathetic and other nerves, and by exposing for 
experimentation even the heart itself, enormous numbers of 
physiological facts have been deduced from the phenomena ob¬ 
served. These facts, like all others in physiology, have a bearing 
on pathology, but have not yet been practically utilized to any 
extent in medicine. We have learned, however, that the physi¬ 
ology of the heart-beat, the innervation of the iris, the localization 
of cerebral and spinal tracts, etc., etc., are exceedingly complex 
studies. 
When a galvanic current traverses a motor nerve, the muscle 
supplied by that nerve contracts, but the contractions will only 
recur upon the makes and breaks of the circuit (or upon changes 
of the strength of the current), which, if they be sufficiently 
rapid in succession, will induce an “artificial tetanus,” corre¬ 
sponding to the tetanic action of volitional muscular contraction. 
That an electric current traverses an acting muscle or nerve in 
health has long been demonstrated by the galvanometer. These, 
no doubt, are both caused by and causative of chemical action, 
and certain drugs, such as curare-varatria, etc., are known to 
modify or even obstruct these currents. 
Sudden reversals of polarity of the electrodes induce powerful 
reactions; but the direction of the current has but little influence 
upon the contractions, for all currents diffuse in subservance to 
physical law. Fatigue, impoverished blood supply and lowered 
temperature certainly modify the contractions in a definite man¬ 
ner; but the altered reactions of morbid processes are indefinite. 
The part of a muscle excited by a current is electro-negative to 
all other parts, while, in a transverse section of muscle, the cur¬ 
rents run from the equator or positive pole to the cut extremities. 
