The Action of Simple Reagents on the 

 GangHa of Arthropods 



WILLIAM A. HILTON 



The ganglia of centipedes and especially those of isopods {Por- 

 cellio) were removed, placed in various fluids, sectioned and stained. 

 The ganglia were either taken from the decapitated animals and 

 placed in the various reagents or they were first fixed in boiling 

 water and then placed in the fluids. All the specimens were treated 

 alike after remaining for a time in the first fluid, all were carried 

 through the alcohols, cleared, etc., sectioned, stained in eosin and 

 methylene blue and mounted. 



Similar experiments are being carried on in this laboratory with 

 the brains of mammals. Differences in detail between the two 

 investigations may be due in part to differences in penetration. The 

 cells of arthropods are very near the surfaces of the ganglia. 



The general effects of some of the reagents used are given. 



Acetic acid 107o after fixation with hot water. Cells deep blue, 

 fibers pink. Overstained blue in the fibrous part settles in a uniform 

 deep color. There is a fine network of pink strands outside the 

 cells. Some cells are with vesicles or light spots but most are pink 

 like the fibrils about. The nuclei are a deep uniform blue. In 

 some places all cells seem to take a deep blue color. 



Oxalic acid saturated solution. Used directly upon the fresh 

 ganglia. Fibers uniform, cells blue, nuclei clear, fibrils well pre- 

 served. 



Tannic acid, 10%, for fixation. Brown, even blue stain in parts. 

 Not good results. 



Pyrogallic acid, 10%. Uniform deep blue, fibrils seen on the 

 surface. 



Stronger acids seemed to act too quickly, unless used in dilute 

 solutions. No marked results. 



