Nerve Cord of Cambarus Clarkii. 335 

 158 (1905) 



Chemical stimulation of the nerve cord of Cambarus clarkii. 



By A. R. MOORE. 



[From the Physiological Laboratory of Rutgers College, New Bruns- 

 wick, N. J.] 



A preparation of the central nervous system of crayfish was 

 made by decapitating the animal and uncovering the nerve cord 

 of the posterior abdominal segments. Application of a stimula- 

 ting substance to this portion of the cord resulted in convulsive 

 movements of the thoracic appendages. Stimulation was ob- 

 tained from application of excitants of the first class, BaCl 2 , KC1, 

 Na 3 citrate, in concentrations isosmotic with the animal's blood. 

 Tetraethylammonium chloride in M/64 concentration acted as a 

 strong excitant. Of the excitants of the second class, camphor, 

 strychnine, atropine, picrotoxin, nicotine, caffeine and phenol 

 were active. Creatine alone showed no effect. The central nerv- 

 ous system of Cambarus therefore differs from that of Lumbricus 1 

 in being sensitive to the action of nicotine, phenol and caffeine. 

 The two forms are alike in being insensitive to creatine, and in the 

 fact that the latent period for chemical stimulation is very short, 

 less than a minute. 



159 (1906) 



The respiratory rate of the nerve cord of Cambarus clarkii. 



By A. R. MOORE. 



[From the Physiological Laboratory of Rutgers College, New Bruns- 

 wick, N. J.] 



The rate of production of C0 2 of the nerve cord of Cambarus 

 was determined by means of the colorimetric method previously 

 described. 2 The nerve cord was removed entirely freed from 

 other tissue. Stimulation due to cutting was only momentary. 

 It could be shown, by leaving the cord attached at the anterior 



1 Moore, A. R., J. Gen. Physiol, 1921, iv, 29. 



2 Moore, A. R., J. Gen. Physiol., 1918-19, i, 613. 



