368 
PROFESSOE MATTEUCCI’S ELECTRO-PHYSIOLOGICAL RESEARCHES. 
the experiment was made before or after having touched the nerve in other points; 
consequently in all my subsequent experiments I have never employed any other method 
than the differential method which I have already described. 
I prepare on a fowl two sciatic nerves, and lay them side by side on the two cushions 
of glasses filled -with spring water, in which I plunge the electrodes of a pile of ten small 
elements (zinc, charcoal, and saltwater). The current divides itself equally between the 
two nerves. I leave the circuit closed for a time, varying from five to twenty minutes. 
I then lay the two nerves in opposition on the gutta-percha holder, and bring them 
into communication with the galvanometer. No trace of differential current is to be 
detected, while each of these nerves gives a secondary current of from 40° to 50° 
I shall now describe briefly the results obtained by studying the influence exercised 
by various physical and chemical conditions, to which the nerve was subject, on its 
electromotor power. 
I prepare in the usual way two sciatic nerves of a fowl. I put one of these nerves 
into a glass tube, which is left for fifteen minutes in a refrigerating mixture ; at the end 
of this time the nerve thus cooled is exposed to the air until it acquires the same tem- 
perature as the other nerve. Both nerves are then disposed so as to be traversed by the 
same current, after which they are reunited in opposition and tested at the galvano- 
meter. I find that the secondary electromotor power of the nerve which had been 
cooled had sufiered great diminution. 
I take two similar sciatic nerves, and immerse one of them in water at+50° or 60° C., 
leading the other nerve intact. I send a current, as in the former experiment, through 
both nerves, and find the secondary electromotor power strongest in the nerve which 
was not heated. 
I prepare on another fowl two other sciatic nerves; I crush or compress one, 
and leave the other intact. After these two nerves have been simultaneously subjected 
to the passage of the current, the secondary electromotor power is greatly weakened 
in the nerve which has been crushed. 
Portions of sciatic nerve which have been held for a few minutes in an alkaline solution 
containing -^oo weight of potassa, lose completely their secondary electromotor power. 
Immersion of the nerve in alcohol produces the same result. If the nerve is kept for a 
very long time in distilled water, the secondary electromotor power is weakened. It is re- 
markable that the time which may elapse after the passage of the electric cun-ent in the 
nerv'e and the washing of the nerve in water, exercises no influence on the secondaiy 
electromotor power of the nerve. If two sciatic nerves are exposed to the same current, 
but successively, no difierence is found between them even when there has been an 
interval of from fifteen to twenty minutes between the electrolysation of the two nei-ves. 
After having subjected two similar nerves to the passage of the current, if one of them is 
afterwards held for a few seconds in distilled water, its secondary electromotor power is 
unaltered. 
A nerve subjected to the passage of the current, first in one direction and then in 
