CHEMICAL STIMULATION OF THE NERVE CORD OF LUM- 

 BRICUS TERRESTRIS. 



By a. R. MOORE. 

 {From the Physiological Laboratory, Rutgers College, Ne-d.' Brunswick, N. J.) 



(Received for publication, May 27, 1921.) 



Nerve cells of different functions cannot be differentiated histolog- 

 ically by staining methods. In order to prove chemical differences 

 it is necessary to affect the function of a given type of neuron by 

 the action of a chemical agent. Thus Baglioni^ has demonstrated a 

 chemical difference between sensory and motor cells in the frog and 

 the squid, by showing that phenol is an excitant for the motor ganglia 

 alone while strychnine stimulates the sensory ganglia only of these 

 forms. MaxwelP has shown that the nerve cells of the mammalian 

 cortex are stimulated by one class of substances which includes creatine 

 and strychnine, but that such substances do not act on medullated 

 nerve fibers. Only certain salts, such as the calcium precipitants and 

 barium compounds, act upon medullated fibers. On the other hand 

 these salts do not stimulate the gray matter of the brain. Tetra- 

 ethyl-ammonium chloride is an exception in that it acts upon struc- 

 tures of both types.* 



It is possible that chemical differences exist between nervous sys- 

 tems of various forms.* For example, coelenterates give no spasm 

 response to strychnine, but echinoderms do, provided the concen- 

 tration of alkaloid is sufficiently high, while cephalopods are as sen- 

 sitive to strychnine as vertebrates are. On these grounds Parker^ has 

 suggested that strychnine might be used as a test for the presence 

 of synapses, since sensitivity to strychnine on the part of different 



1 BagUoni, S., Z. allg. Physiol, 1905, v, 43. 



2 Maxwell, S. S., J. Biol. Ghent., 1906, ii, 183. 



3 Maxwell, S. S., Am. J. Physiol., 1918-19, xlvii, 283. Loeb, J., and Ewald, 

 W. F., /. Biol. Chcm., 1916, xxv, 377. 



* Moore, A. R., Proc. Nat. Acad. Sc, 1917, iii, 598. 



'Parker, G. H., The elementary nervous system, Philadelphia, 1919, 208. 



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