M On the Pneumogastyic and Sympathetic Nerves^ S^c. [tfan. %1, 



one endowed with those parts thought most essential to Kfe, the cerebellum 

 and medulla oblongata. 



Since the foregoing paper was communicated, the author has had the 

 opportunity of examining two anencephalous foetuses which had been pre- 

 served for many years in the Museum of St. George's Hospital. In the 

 first specimen examined the bones forming the roof and sides of the cranium 

 were wanting, as well as the greater part of the basis behind the foramen 

 magnum ; the brain was absent, and the bony cavity was not formed. 



In this instance nerves were seen passing through foramina in the basis 

 of the cranium. There was no spinal canal, though a membrane from 

 which nerves proceeded occupied the position of the spinal cord. At the 

 commencement of this there was a round body of the size of a small bean, 

 of nervous substance, which was exposed most clearly before the prepara- 

 tion was removed from the bottle in which it had been preserved. The 

 connexion was easily seen between this body and the spinal membrane, and 

 nerves proceeded from its under surface in different directions. 



There were small pieces of cartilage, apparently portions of vertebrae, 

 found here and there in the spinal region, but there was no sacrum, and 

 the rectum was exposed. 



Such were the general appearances presented by this foetus. In other 

 respects it was well developed. The large venous and arterial vessels were 

 seen to supply appropriate parts. 



The pneumogastric nerves were traced by following their branches in the 

 neck upward and downward. That on the left side was seen perforating the 

 floor of the cranium, with a ganglionic enlargement formed on it soon after 

 it issued from the canal, and thence passing downwards to supply the usual 

 organs. The nerve on the right side was not clearly traced through the 

 floor of the cranium ; but as there w^as an opening corresponding to that on 

 the left side, there is no reason to doubt the similarity between the tw^o 

 nerves. 



A question which naturally presented itself on perceiving the small round 

 body described above, was whether this might not correspond to the medulla 

 oblongata. That this is not probable appeared from the fact that the 

 pneumogastric nerves left the cranium at a distance of nearly two inches 

 from it, and no connexion could be seen to exist between them and that 

 body. No history has been preserved of this foetus ; so that whether it 

 showed any signs of independent existence cannot be ascertained. 



The distribution of the nerves in the thorax presented nothing very 

 abnormal, the various parts being supplied with their proper branches. The 

 sympathetic nerve was of small size on both sides, and its extent greatly 

 diminished. 



The second of these dissections bore some resemblance to the foetus 

 described in the paper, with the exception that there was no trace of cere- 

 bral matter whatever. A membrane from which nerves proceeded was all 



