68 Journal of Comparative Neurology and Psychology. 



stimulated l)y a series of induction shocks. The experiments were made 

 upon doo-s, and the sciatics of both legs were taken for observation. 

 One sciatic was removed as soon as the animal Avas anaesthetized suffi- 

 ciently for the operation. The nerve was placed at once in the moist 

 chamber, and its action current was determined at intervals of half an 

 hour, as long as a res})onse could be obtained to stimulation. With 

 the values of these action currents as ordinates, a curve was con- 

 structed, showing the duration and variations of irritability in the 

 "unansesthetized nerve" during the period of ol)scrvation. The other 

 sciatic was left in the animal for a period of four to six hours, and 

 during this time the animal was kept completely anassthetized by mor- 

 phia and ether. At the end of this period, there was a considerable 

 fall in rectal temperature (30°-3i° C). The anesthetized nerve was 

 then removed, and galvanometric observations wei-e made similar to 

 those just described. The results obtained show that the nerve re- 

 moved from the anaesthetized (and cooled) animal survives for a longer 

 period than that taken from the animal at the beginning of the period 

 of anaesthesia, the difference in time of survival being as much as four 

 or five hours. A more marked difference, however, is that the 

 "anaesthetized" nerve exhibits throughout a much greater irritability. 

 The curves obtained were irregular; but that for the "unanaesthe- 

 tized " nerve shows a small increase in irritability occuring shortly after 

 the excision, and soon followed by a steady decline to zero; while that 

 for the "amEsthetized " nerve exhibits, as its most marked feature, a 

 large and sudden increase in irritability coming on some hours af]:er 

 the excision, and followed by a more rapid fall to zero. 



The Condition of the Vaso-con stricter Neurones in ^^ Shock," by W. 

 T. Porter and W. C. Quinby. The normal fall of blood-pressure 

 produced by stimuli of uniform intensity applied to the central end of 

 the depressor nerve was measured in the rabbit and the cat. In the same 

 animals the shock was then brought on, aiM the measurements repeated. 

 The experiments make clear (i) that the normal percentage fall 

 in blood-pressure may be obtained bv stimulating the depressor nerve 

 during shock ; (2) if during shock the blood-pressure be raised to nor- 

 mal values by the injection of suprarenal extract or normal saline so- 

 lution, and the depressor nerve be stimulated while the pressure is still 

 high, the absolute fall in blood-pressure may be as great as it was in 

 the same animal [before shock liegan. Exhaustion of the vaso-con- 

 strictor neurones cannot therefore be the essential cause of the symp- 

 toms termed shock. 



Denuinstration of Rablnfs Nerves, Showin^^ the Effect of Ligation 



