98 THE SIGNS OF LIFE [LECT. 



muscular movement by curare, and therefore preliminary No. 2 

 is artificial respiration. 



It is now 5.10 P.M.; the cat has been dead twenty-five 

 minutes. I have therefore five minutes time to further explain 

 my meaning. The surviving tissues are dying ; the junction 

 between motor nerve fibre and muscular fibre is dying ; the 

 junction between secretomotor fibre and gland cell is also 

 dying ; but, according to my experience, the first will die in 

 thirty, the second will die in sixty minutes. I have therefore 

 a margin of thirty minutes during which excitation of that 

 packet of nerve fibres called the sciatic nerve will not cause any 

 movement of the limb (nor, therefore, any possible shifting of 

 contacts or other disturbance), but will cause an activity of the 

 cutaneous glands.* 



You will find as a book datum (and as a printed datum it is 

 a very satisfying datum) that the independence of secretomotor 

 nerves is proved by the fact that after death (of the cat), when 

 the circulation, and therefore vasomotor, effects are out of count, 

 beads of sweat are made to appear on the carefully wiped pad 

 by excitation of the sciatic nerve. 



I have never succeeded in witnessing these beads of sweat, 

 and will not therefore make the attempt to demonstrate them 

 to you ; but I shall show you by means of the galvanometer, 

 within this margin between the thirtieth and sixtieth minute 

 post-mortem, that the excitation of the sciatic nerve on one side 

 (and on the other), causes a marked physical alteration in the 

 skin of the pad, first on one side and then on the other. Cats 

 differ, and I will not answer for my times to a minute, but it 

 is now thirty-five minutes post mortem felis, and I am well within 

 the margin. The two hind pads are connected with the two 

 terminals of the galvanometer. I don't know which is which, so 

 I test my connections with a bit of zinc, by touching the 

 two terminals on the operation table with which the two 

 galvanometer terminals are connected. Touching the terminal 

 of the left pad with the bit of zinc, while my finger is on the 



* The longest period recorded in my notes has been 2 hrs. 15 mins., in 

 the case of a particularly well-nourished cat. 



