Mr H. F. Baxter on Muscular Power. 199 
the lower part of the thigh and drawn down, by these 
means the risk of wounding or lacerating the vessels cross- 
ing the nerve in the middle of the thigh was avoided. 
In tying the tendo-Achillis to form the loop, unless care 
be taken, the vessel running along its inner border will be 
wounded when passing the needle. 
2. Not to tie the Muscular Fibres. If, in tying the tendo- 
Achillis, the loop be carried too high up, the muscular fibres 
will be included; in this case they soon become lacerated 
and torn through, when the weights are added to the scale. 
3. To keep the Sciatic Nerve away from the surface of the 
Thigh. It frequently happened that during the struggles 
of the animal the sciatic nerve would come into contact 
with the surface of the thigh, although its extremity was 
resting on the bibulous paper. Under these circumstances 
contractions may not be excited in the muscles when the 
current is passed, and this I believe to be due to the cur- 
rent instead of being transmitted along the nerve, through 
the muscle, was thus transmitted by the surface of the 
muscle or the skin of the thigh. The nerve should be kept 
straight away from the thigh. 
4. The Electrodes should be clean. Thisis a most import- 
ant circumstance to be attended to, especially with the 
electrode employed to touch the surface of the tendon. 
When the electrode is brought into contact with the sur- 
face of the tendon it becomes covered with the fluid, and a 
crust is soon formed upon it which acts as a non-conductor ; 
to remedy this, it is necessary to frequently scrape it, so as 
to present a fresh and clean surface ; mere wiping is not 
sufficient. The surface of the wire in contact with the 
bibulous paper should be carefully looked to and frequently 
scraped, and the paper upon which the nerve rests be kept 
moist, and the nerve itself occasionally slightly moistened. 
0. When exciting the muscles to contract, the tendo- 
Achillis should be touched lightly and quickly. If the elec- 
trode be allowed to remain too long in contact with the ten- 
don, we have two contractions, one on making, the other 
on breaking, contact. If the tendon be struck too forcibly 
_ the muscle will be thrown out of its perpendicular position, 
and thus elevate the weight and move the index. 
