TRANSACTIONS OF SECTION I. TAL 
common path, some reflexes excluding others and producing inhibitory phenomena, 
some reflexes reinforcing others and producing phenomena of ‘bahnung.’ 
Intensity of stimulation, species of reflex, fatigue, and freshness, all these are 
physiological factors influencing this interaction of the arcs—and under patho- 
logical conditions there are many others—e.g. ‘shock,’ toxins, &c. Hence 
follows successive interchange of the arcs that dominate one and the same final 
common path. We commonly hear a muscle—or other effector organ—spoken of 
as innervated by a certain nerve; it would be more correct as well as more 
luminous to speak of it as innervated by certain receptors; thus, the hip flexor, 
now by this piece of skin, now by that, by its own foot, by the opposite fore-foot, 
by the labyrinth, by its own muscle-spindles, by the eye, by the ‘motor’ cortex, 
&ce. This temporal variability, wanting to the nerve-net system of medusoid and 
lower visceral life, in the synaptic system provides the organism with a mechanism 
for higher integration. It tits that system to synthesise from a mere collection 
of tissues and organs an individual animal. The animal mechanism is thus 
given solidarity by this principle which for each effector organ allows and 
regulates interchange of the arcs playing upon it, a principle which I would 
briefly term that of ‘ the interaction of reflexes about their common path.’ 
The following Papers were read :— 
1. On Reflex and Direct Response to Galvanic and Faradic Currents. 
By Professor J. A. MacWILtiAm. 
The author’s experiments had proved that eels were remarkably responsive to 
electrical currents, a responsive fin movement of a reflex nature being readily 
elicited. The negative pole was usually the effective one. Frogs, newts, carp, 
&c., gave negative results. After death of the spinal cord much stronger currents 
were necessary to evoke any movement, and these were of a different character, 
being direct responses of the muscles. 
2. On the Metabolism of Arginin. By Professor W. H. Tuompson, I/.D. 
If arginin, an important crystalline base obtained by the cleavage of proteids, 
is administered to animals, either by injection or with the food, from 80 per cent. 
to 90 per cent. of its nitrogen is excreted as urea. In the laboratory only 50 per 
cent. of the nitrogen can be split off from arginin as urea, the remainder appearing 
as ornithin. Hence in the body the ornithin nitrogen is also converted, largely or 
entirely, into urea. 
3. On the Relation of Trypsinogen to Trypsin. 
Sy Professor E. H. Sraruine, 7.2.8. 
Pawlow and his pupils have shown that fresh pancreatic juice, obtained from 
a pancreatic fistula, possesses no power of digesting proteids, but that after it has 
been acted upon by intestinal juice it gains that power. He concluded that the 
intestinal juice contained a ferment (enterokinase) which acted upon the trypsi- 
nogen of the fresh pancreatic juice, converting it into trypsin. Against this view 
French observers have brought forward another—viz., that the interaction of the 
two secretions is analogous to that of the cytases, and that the trypsinogen can 
only act upon proteids in the presence of enterokinase. Bayliss and Starling have 
studied the action of enterokinase upon trypsinogen, and by observing the rate of 
its action have, by finding that it follows the usual laws of ferment action, 
brought strong evidence to prove that Pawlow’s view is the correct one, and that 
enterokinase is a ‘ferment of ferments.’ They have now further evidence in the 
same direction. By injecting rabbits with solutions of enterokinase they found 
that an antibody could be produced which, acting upon the enterokinase, was 
