72 



If the comparison is made four or five weeks after the opera- 

 tion, then the non-paralyzed limb has a greater irritability than 

 the three paralyzed, and, from these three, the one deprived only 

 of the cerebral action has a greater irritability than the two 

 others. 



The same experiments made on other animals than frogs, i. e. 

 on guinea-pigs and rabbits, have given like results. I shall pub- 

 lish the details of these last experiments in a special paper, in 

 which I intend to examine the value of the clinical observations 

 of Marshall Hall, R. B. Todd, Duchenne de Boulogne, and 

 others. I will merely state here, that in many cases it is almost 

 impossible to know what is the difference in the degree of mus- 

 cular irritability in a paralyzed limb, compared with a healthy 

 limb, in a living man or animal. Galvanism and strychnine can- 

 not give us any exact notion in this respect. I ought to add, 

 that if we could know what is the relative degree of irritability 

 in a paralyzed limb, we could not make use of that knowledge 

 for the diagnosis of the seat of the alteration producing the 

 paralysis. On the other side, we do not want to know what is 

 the degree of irritability in order to establish such a diagnosis. 

 It will be, almost constantly, easy to know whether a paralysis is 

 a cerebral or a spinal one. The existence of reflex actions in 

 the paralyzed parts, is sufficient to prove that there is a cerebral 

 paralysis, and the absence or the slight degree of these actions 

 will prove that there is a spinal paralysis. 



The following conclusions may be drawn from the facts 

 above related, and from others that I have not yet published. 



1st. The degree of muscular irritability in paralyzed parts, 

 becomes rapidly greater than in the healthy parts, but, after a 

 variable length of time, it diminishes, and, as it is well known, 

 it may disappear. 



2d. The muscles deprived of the action of both the brain and 

 the spinal marrow, become rapidly more irritable than the mus- 

 cles deprived only of the action of the brain, but, after a certain 

 time, there is also in them a more rapid diminution of irritability 

 than in the others. 



3d. It appears certain that the muscular irritability never 



