DEAN ON THE MEDULLA OBLONGATA. 505 



lished by tlie New Sydenham Society. If Dr. Dean is right, the 

 views of the celebrated Utrecht Professor are wrong ; and in that 

 case it were well that they should be recalled or arrested before they 

 have sunk too far into medical practice. Schroeder van der Kolk, as is 

 well known, having satisfied himself that there was little or no direct 

 decussation between the two hypoglossal nuclei, that, on the other 

 hand, the two olivary bodies not only were largely united with each 

 other, but likewise possessed special fascicules (also observed by Len- 

 hossek), connecting each with the hypoglossal nucleus of the same 

 side, and having observed that in the animal series the development 

 of the olivary bodies corresponded with the amount of movement 

 possessed by the tongue, drew up a theory that these structures 

 were intimately concerned in or presided over the processes of 

 deglutition and, more especially, of speech. And he supported this 

 opinion w4th facts gathered from pathological researches. Dr. Dean, 

 however, states, that there is, at least, some decussation between the 

 two hypoglossal roots, which, therefore, may be presumed to be com- 

 petent of bilateral action without the intervention of any third body. 

 In the cat he finds this decussation very marked. He denies, more- 

 over, the existence of any peculiar communication between the 

 olivary bodies and the hypoglossal nuclei, and hence rejects Schroeder 

 van der Kolk's theory of the special function of the former. At the 

 same time he admits that some fibres from the hypoglossal nuclei, as 

 well as from all the other nuclei of the medulla, ' pass among the 

 cells of the olivary bodies, and, in many cases, are doubtless con- 

 tinuous with their processes.' And dwelling on the fact that those 

 bodies are also largely connected with the system of arciform fibres, 

 with the system of longitudinal fibres and with the antero lateral 

 nucleus and caput cornu, he is led to agree with Clarke in attri- 

 buting to them a * co-ordinating influence.' 



The remarkable nuclei, which were first pointed out by Clarke^ 

 and which have received the name of 'upper olivary bodies,' were 

 thought by Schroeder van der Kolk to be especially connected with 

 the facial nerve. And their great development in carnivora and. 

 feeble conformation in herbivora led that observer to regard them as 

 organs for the expression of passion by facial movements. Dr. Dean, 

 has traced the upward development of these bodies from two nucleic 

 existing on the outside of the lower olivary bodies, which he has. 

 especially described and named the ' antero-lateral nuclei,' from their 

 position in the antero-lateral columns. He considers them as being, 

 N.H.R.— 1865. 2 M 



