^O HUBER. [Vol. XVI. 



experiments of the following nature : the spinal cord of frogs 

 was destroyed by inserting a hot needle through the peripheral 

 end of the spinal canal ; anaesthetized frogs stand this very 

 well. In the frogs so operated upon, the posterior extremities 

 seemed entirely paralyzed. At the end of five, ten, and twenty- 

 five days a certain number of frogs were injected with meth- 

 ylene blue, with a view of staining the sympathetic ganglia. It 

 was found, however, that even in frogs in which a portion of 

 the cord had been destroyed twenty-five days previous to the 

 injection, the nerves were not as yet degenerated; even the 

 motor endings, in the sartorius, for instance, could be stained 

 very easily. The sacral sympathetic ganglia showed, in all but 

 one instance, the spiral fibers. This experiment (of ten days' 

 duration) seemed at first conclusive, as only a few spiral fibers 

 and baskets were stained ; the unipolar ganglion cells stained 

 much more readily than usual. Later experiments, where a 

 longer time elapsed between the primary operation and the 

 injection, did not, however, corroborate the above result. It 

 may be stated that not much reliance can be placed on these 

 experiments, as they were made on " winter frogs " in the early 

 spring, at a time when it is well known that their metabolic 

 changes are at their lowest. This, I think, may account for 

 the fact that no degeneration of nerves was observed, dissection 

 showing that the posterior portion of the spinal cord was com- 

 pletely destroyed. It is my aim to repeat such experiments on 

 more suitable frogs. 



The following brief summary of the results obtained in the 

 study of the sympathetic ganglia of Amphibia may here be in 

 place : 



i) The sympathetic neurons of the frog are unipolar cells, 

 the neuraxes of which (straight processes) innervate involuntary 

 muscle and gland tissue (Kolliker). 



2) Entering the sympathetic ganglia through the white 

 rami, or through the interganglionic nerves, are seen medul- 

 lated fibers, probably of cerebro-spinal origin, which fibers divide 

 in the ganglion into two, possibly three, fibers, also medullated ; 

 at various places in the course of these fibers non-medullated, 

 collateral branches are given off, which, with or without further 



