Literary Notices. Iv 



especially evident in the case of the sensory nerves and attains its high- 

 est development in the retina and auditory nerve. . . . There can 

 be no difficulty , then, in supposing that at the sensory terminal distribu- 

 tion generally, force is continuously generated and maintained at a cer- 

 tain degree of tension, which is balanced and resisted in the nerve cen- 

 tres by force there generated. In the same way the relation between 

 the motor nerve endings and the motor nerve nuclei in the cord 

 would be one of balanced tension. The muscular tonus which 

 gives rise to the knee jerk would appear to be the peripheral ex- 

 pression of such a relation." This relation of mutual tension and 

 reciprocal control finds its expression in a great variety of very 

 familiar activities and inhibitions, including trophic influence. In 

 the latter case, "the nerve endings in skin and muscles are identi- 

 fied in their nutrition with the structures to which they are distributed. 

 The muscles, indeed, may almost be looked upon as end-organs of the 

 motor nerves. Through this community of structure and nutrition with 

 the nerve terminations it seems to me that the tissues will take part in 

 the maintenance of the tension between periphery and centres, while 

 in turn the nerves will influence the nutritional processes in the tissues 

 just as by way of analogy, heat and electricity condition chemical 



action." 



c. J. H. 



The Central Connections and Relations of the Trigeminal, Vago-Glosso- 

 pharyngeal, Vago-Accessory and Hypoglossal Nerves. 



Under the above title Dr. Wm. A. Turner presents some interest- 

 ing results in '^iQ Journal of Anatomy and Physiology for October, 1894, 

 based upon a study of silver preparations of newly-born kittens, Wei- 

 gert-Pal preparations of an eight-months' human foetus, experimental 

 work on monkeys and cases of bulbar paralysis. We offer his sum- 

 mary : 



1. The hypoglossal nucleus is solely a nucleus of origin; the 

 efferent fibres are the axis-cyhnder processes of the cells of the nucleus 

 of the corresponding side, and have no direct connection with opposite 

 nucleus, or with the nuclei of Roller and Duval ; the afferent hypoglos- 

 sal fibres are derived from the pyramids, forming in chief p^-vt the ffl>ras 

 proprice, also from the reticular formation, and possibly from the fillet. 



2. The nucleus anibiguus is the nucleus of origin of the motor 

 fibres contained in the roots of the glosso-pharyngeal, vagus, and vago- 

 accessory nerves, and innervates, among other structures, the levator 

 palati and internal thyro-arytenoid muscles. The afferent fibres of the 

 glosso-pharyngeal and vagus roots are the axis-cylinder processes of the 



