VOL. LXXXIII.] PHILOSOPHICAL TRANSACTIONS, 315 



birth, are supported without any inconvenience. The brain has been frequently 

 found very incompletely formed, and sometimes not at all, yet still there have 

 been nerves. In other cases, where the brain has been perfect, the spinal 

 marrow has been deficient in a great part of its extent, and sometimes through- 

 out. Both these occurrences are sufficient to prove, that, at any rate, that in- 

 timate connection of the brain and nervous system, which takes place after birth, 

 is not necessary for the formation of a body in other respects perfect. But still 

 it would remain doubtful, whether any regular structure could be formed, with- 

 out any vestige of either brain or nerves; and therefore without a possibility of 

 their influence, in any manner, toward such structure. 



The monster now under consideration is so extremely simple, in this respect, 

 that it cannot be exceeded by the most simple animal known. It may be ob- 

 jected however, that there might be brain, or nervous fibres, in this monster, 

 but that they might, in the dissection, be destroyed. But, in the first place. 

 Dr. C. observes, that the parts were examined too carefully for such a suspicion ; 

 and, in the next, as there were no bones representing either the cranium, or 

 spine, or os sacrum, it is not probable that their contents should exist in any 

 other situation. Another objection may perhaps be taken from the anastomosis 

 of the vessels of the monster, with those of the perfect foetus, and it may be 

 assumed, that the nervous influence might be transmitted, in this way, along 

 the vessels; but there is very good reason for believing that the vessels of the 

 placenta have no nerves, since, when we cut the navel-string, neither the 

 mother, nor the child, expresses the smallest sign of sensation: and indeed, 

 even if they had nerves, it is still very unlikely that, merely by such anastomosis, 

 any nervous influence could be conveyed. Dr. C. thinks it right to answer ano- 

 ther possible objection which may be made, viz. that nervous matter may be 

 co-extended, or co-existent with all other animal matter, and that, of course, 

 it is of no consequence whether there be any sensorium, or reservoir of im- 

 pressions, &c. or not; because the stimulus, which produces action, must re- 

 side in parts, as well as the other substance of which they are composed. 



Now, though this may possibly be true, we have no evidence of the fact 

 sufficiently satisfactory to carry conviction along with it. On the contrary, there 

 seems to be good reason for entertaining an opinion, that nervous influence is 

 conveyed from the brain downwards. If we are right in this conjecture, which 

 is warranted by the experiment of tying, or cutting nerves, then the existence 

 of the nervous fibre, like that of a string of a musical instrument, would be 

 inactive, unless it received an impression, which, with regard to the nerves, 

 should come from the brain. The whole of the actions of this monster then, 

 must have been those of the vascular system entirely; and these seem to have 

 been capable of forming bone, skin, cellular substance, ligament, cartilage, in- 



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