DUAL CHARACTER OF THE BRAIJf. 9 



npon one-half of the brain, in some individuals at least, as 

 being able to control voluntary movements in the two sides 

 of the body. If so, certainly the point I have in view— that 

 is, to show that we have two brains— is established as regards 

 voluntary movements. We have certainly two brains as regards 

 voluntary movements; and if it is found in most cases that even 

 a slight injury limited to a small part of the brain will produce 

 a paralysis on the opposite side, or sometimes on the corre- 

 sponding side— if that is found, it is on account of the principle 

 which I mentioned a moment ago ; that is, that an irritation in 

 any part of the brain can affect functions in other parts through 

 transmitted irritation. And I can say in regard to voluntary 

 movements what may be said as to worms in the bowels, as 

 well as an irritation in a tooth, in the stomach, in the lungs, in 

 tne heart, or an irritation in the skin; in other words, an irri- 

 tation wherever there is a nerve subject to be irritated, all can 

 produce a paralysis as well as an irritation in a part of the 

 brain. And therefore, when we see a slight alteration in a very 

 limited part of the brain cause a complete paral3^sis on the 

 opposite side of the body, we are not to conclude tliat it is 

 owing to the loss of function of voluntary power where the 

 disease exists, but that it depends upon an irritation starting 

 from the place where we see the disease, and acting upon remote 

 parts so as to produce the loss of the function. The mere fact, 

 that a disease exceedingly limited in extent can produce a com- 

 plete paralysis In the opposite side of the body, is sufficient to 

 show that it does not depend on the loss of the function of 

 will; for the cause of motion of one-half of the body cannot be 

 located in a very limited part of the brain. If it were tlie other 

 side of the brain which produced that complete paralysis, if 

 we fonnd that paralysis is more or loss extensive, more or less 

 durable according to the extent of the disease in one-half of the 

 brain, then we might conclnde that the disease has destro3'ed 

 the power of will in that half of the brain, and thereby produced 



