LOCOMOTION IN BATRACHOSEPS WITH SEVERED 



NERVE-CORD. 



CHARLES D. SNYDER. 



The earlier discoveries in the anatomy and physiology of the 

 nervous system led to the conception that the nervous mechanisms 

 of the human body were under the control of a single center, the 

 brain. 1 Discoveries, which have been made in the field of com- 

 parative physiology during the past fifty years, however, are lead- 

 to a very different conception. 



Not only the spinal cord, 2 but also the brain, 3 is being regarded 

 not as a single nerve-center but as a segmental series of many 

 nerve-centers. Furthermore the idea is gaining ground that true 

 nerve-centers are probably not so greatly differentiated one from 

 the other, that their respective protoplasmic contents are not 

 so different in nature, as was once supposed. On the other hand 

 it is pointed out that specific differences in the nervous substance 

 is to be looked for in the sense-organs, in the peripheral nerve- 

 substance, rather than in the central organs. Accordingly the 

 central nervous system is to be regarded primarily as a special 

 conduction substance by means of which the sense organs are 

 able to communicate with the various physiological structures in 

 which the efferent nerve-fibers find their termination. 4 



The observations reported in the present paper furnish addi- 

 tional evidence in support of this segmental theory of the central 

 nervous system. In order to make the viewpoint of interpreta- 

 tion of results clearer the work of two other authors will be first 

 briefly reviewed. 



Friedlander 5 observed that coordination of the longitudinal 



1 Schiff, " Lehrbuch der Physiologic," 1858, s. 194. Foster, " History of Physi- 

 ology," 1901, p. 257 ft". Steiner, " Die FunctionendesCentralnervensystemsundihre 

 Phylogenese," 2te Abtheilung, Die Fische, 1888, s. 35. 



2 Sherrington in Schaefer's "Text-book of Physiology," p. 816. Loeb, Arch. f. 

 d. ges. Physiologic, Bd. 96, s. 536, 1903. 



3 Griinbaum and Sherrington, Proc. of Roy. Sac., Vol. 69, 1901. 

 1 Loeb, "Comparative Physiology of the Brain and Comparative Psychology," 1901. 

 1 Friedlander, B., " Physiologic des Centralnervensystem," Arch. f. ges. Physiol- 

 ogie, Bd. 58, s. 168, 1894. 



280 



