724 DR FRASEB ON THE PHYSIOLOGICAL ACTION 



of muscles from which they had disappeared ; and it was then observed that the 

 whole of a muscle seldom twitched at once, but portions of it separately and in 

 succession. I frequently removed a muscle from the dead body, and found that 

 these twitches still continued. In one experiment, where the sartorius had been 

 cut out of a dog, these spasms rapidly followed each other in separate portions of 

 its substance, during ten minutes. Their duration after death varied greatly. 

 Occasionally they ceased before the motor nerves had lost their function, while 

 they frequently continued after their paralysis. The latter effect was well shown 

 in an experiment where seven grains of extract were given to a large dog, by 

 injection into a jugular vein : death, with stoppage of the heart's action and of the 

 respiratory movements, took place in eleven minutes; in twenty-five minutes 

 afterwards, the sciatic nerves were paralysed ; and these extraordinary muscular 

 twitches continued for other twenty minutes, or for forty-five minutes after the 

 death of the animal. The central nervous system has no influence in causing or 

 originating these quiverings, for division of a sciatic nerve, before the exhibition of 

 physostigma, did not appear to impede their production. I believe the effect is 

 due to the contact of the poison with the muscular substance itself; and this view 

 is supported by the above facts, and by the circumstance that when a ligature was 

 drawn round the posterior extremity of a rabbit, taking care to exclude the sciatic 

 nerve, the muscles of that limb remained unaffected, after the administration of 

 Calabar bean, while those of the body and of the other extremities were twitch- 

 ing in the usual manner. 



Action on the Cerebrum. 



A condition of retained consciousness with marked paralysis opposes the idea 

 of the latter symptom being due to coma. Professor Christison has admirably 

 described the coincidence, in his own person, of retained mental vigour with 

 inability for movement. To distinctly prove the absence of any cerebral 

 explanation for this paralysis, a simple experiment was undertaken. 



Experiment XVI. 



The brain was removed with care from a large frog, and, sometime after this, the animal 

 was found jumping about vigorously* Two grains of extract, suspended in fifteen minims of 



* It appears somewhat startling to assert that complicated movements, of an apparently voluntary 

 character, may continue in frogs after the removal of the brain. I first observed this in an experi- 

 ment in which the spinal cord had been divided at the base of the skull ; and, in describing the con- 

 dition of the frog in which it was seen, I added a qualifying note ascribing the circumstance to 

 incomplete division of the medulla. Since then, I have occasionally observed the same phenomenon ; 

 and the present experiment is conclusive in showing that some of those functions which we are in 

 the habit of ascribing to the cerebral lobes alone, are, in frogs at any rate, shared in by the spinal 

 cord. 



May 1867. — Dr Norris enters into this anomaly, and confirms its occurrence, in his admirable 

 paper on Muscular Irritability, in the " Journal of Anatomy and Physiology," No. 2, p. 221, el seq. 

 He also refers to Lewes (Physiology of Common Life, vol ii.) as having first prominently announced 

 this curious exception to the generally received views on nerve physiology. 



