1011] Nervous System of Corydalis 221 



bipolar nerve cells and nerve plexuses, from tactile hairs and 

 from the surface of the hypodermis. In Corydalis at various 

 times during several years I have tried to determine the motor 

 and sensory parts of each peripheral trunk for the purpose of 

 following them into the central nervous system. To some 

 degree methylene blue stain is of a differential value in deter- 

 mining the nature of nerve trunks, for very often the first 

 neurons to take the stain are sensory, while motor fibers and 

 cells are often slower to turn blue. But this method is not 

 absolutely sure, for there is great variability in the staining 

 reactions of different individuals. The only sure way of telling 

 whether a given branch is motor or sensory is by tracing the 

 nerves to their endings in muscle fibers or from their origin in 

 bipolar sense cells at the periphery. The tracing of a motor or 

 a sensory nerve or tract is not possible in a large number of 

 cases because the stain is incomplete or too dense, but 

 occasional selectively stained preparations enable one to make 

 positive if not complete statements in regard to nerve trunks; 

 that is to say, one can determine surely from a specimen that 

 a large number of branches of a certain nerve are all motor or 

 all sensory, but it would be impossible to say with perfect 

 assurance that the nerve was pure motor or pure sensory 

 because some fine terminations might remain uncolored, 

 especially in the case of a stain which was good for sensory 

 terminations, for there would be a strong probability that soma 

 at least of the fine motor ends would not show. 



The work of Hammar, 'OS, on the nervous system of Cory- 

 dalis has been very helpful, and the general description of the 

 nervous system given by him is so complete that I shall not need 

 to spend time on the gross anatomy of the various ganglia, and 

 in speaking of the several branches of the ganglia 1 shall follow 

 his terminology. 



There are three chief branches breaking from the Lateral 

 trunk of each of the first seven abdominal ganglia, their method 

 of branching from this trunk and from each other is somewhat 

 variable, but these three main parts are easily recognized. 

 Branch 2 is large and comes off quite near the base of the lateral 

 trunk, runs caudally a short distance and then disappears 

 between muscle fibers in a ventral direction. I could not 

 determine it to be anything but a motor branch although some 

 of the fibers from it are among the first to stain and some of 

 them pass not into the ganglion connected with the nerve 



