48 DR. A. D. WALLER ON THE 
shock through the cireuit—first a make, then a break ; the make 
deflection is comparatively small, the break deflection compara- 
tively large. And now, if alternating make and break shocks 
are passed, the galvanometer-spot flies off in the direction of the 
break. The familiar physiological effect known as von Fleisehl's 
deflection is exactly simulated. 
But it is not a physiological effect in this case; for it comes 
off on a boiled holly-leaf and on a thick piece of glazed note- 
paper. The irresistible conclusion is that we have to do with a 
case of variable resistance, smaller to the break than to the make 
shock, as is said to occur in the passage of alternating currents 
through a vacuum-tube. 
Whether this be a valid explanation or not, the fact itself is 
well worth our notice, lest we should confuse a simple physical 
phenomenon independent of the living state with a similar 
physical phenomeuon characteristic of that state. 
§ 34. Sıxru Day.—We have reached our last day, and have 
made little or no use of the accessory piece of apparatus (B A C, 
§ 3) set up on the first day. The apparatus has not “ earned its 
living"; and though we may not hope to make it do so in 
a single day, we may at least do something to justify its 
inclusion in the travelling-box. We shall use it to-day for 
two or three localisation trials, preliminary to a more systematie 
inquiry next year. 
$35. Experiment to deterinine the direction and magnitudes of 
the separate electromotive changes at the two poles of an exciting 
current. 
B C A 
— L L 1 =f. 
Excitation by a single break induction-shock 10,000—, from A 
to B, 7. e. so that A is anode and B is kathode. 
Compensation established between A and B, B and C, and 
A aud C, before and after excitation. 
-B I — A+ 
C 
