76 PHYSIOLOGY. 



prevented from perceiving a brain; and it is as unfair for him 

 to refuse it as it is for us to suppose it. My friend, Dr. Smith, 

 had an opportunity, by new experiments of his own, to ascer- 

 tain a common origin of nerves in some of these animals ; and 

 even where this cannot be perceived, the same conclusion 

 may be drawn from the observation of animals being pos- 

 sessed of certain senses which Haller allows to argue a brain ; 

 so that in several animals in which we cannot point out where 

 a brain lies, yet the presence of eyes is a sufficient proof; to 

 Smith it appeared that hardly any animal is cerebro destitii- 

 tum. Haller adds his last particular ' Movetur quod sen- 

 su caret, et sentiunt corporis partes quae sunt absque motu. 1 

 This only infers the slight supposition, that there is a peculiar 

 organization which is necessary to show the contractile power of 

 fibres, and that there will not be motion without this organiza- 

 tion, so that the motion is not in the medulla cerebri, or in the 

 course of the nerves, because this organization is wanting there. 

 Take notice, that Haller has made a very strange supposi- 

 tion : he says that the muscular fibres are destitute of sense ; 

 but there is no part of the fleshy belly of a muscle which you 

 can touch with the smallest point of a needle in a living animal, 

 that will not give the sense of pain, and shew that it is an or- 

 gan of sense. The only means which Haller has for accounting 

 for this, is to say that the nerves are minutely distributed over 

 the muscles ; but this amounts to the same as the saying that 

 the whole muscle consists of nervous matter, since there is not a 

 point that is not sensible. The fact is, it cannot be demonstrat- 

 ed either one'way or other ; for we cannot trace the subdivisions 

 of the nerves in the belly of the muscle, and show how it is 

 made so large by them ; but if I say that the extremities of nerves 

 are the only sentient part of a muscle, and that they are present in 

 every individual part of it, I say that it is as difficult to suppose that 

 they can be thus distributed, as it is to suppose the other view, 

 and the one is more obvious than the other ; but what follows 

 is absolutely false ' Voluntas motum nervosum ciet et aufert, 

 in insitum nihil potest.' That the will, that a power in the 

 brain excites the nervous power, is true, but we shall see presently 

 that it has also an influence upon the inherent power. So much 

 with regard to this theoretical discussion ; some of you may 



