No. I.] SYMPATHETIC GANGLIA OF VERTEBRATES. 77 



i) In all vertebrates, excepting the Amphibia, the great 

 majority of the sympathetic neurons are multipolar, possessing 

 a varying number of dendrites ; but each cell has only one 

 neuraxis. In Amphibia the sympathetic neurons, with the 

 exception of those found in the coats of the intestinal canal 

 and stomach, which are multipolar, are unipolar cells, as 

 Kolliker has previously stated. In vertebrates other than 

 Amphibia, some few unipolar and bipolar sympathetic neurons 

 are to be found. 



2) In all the vertebrates examined chromophile granules 

 were found. One relatively large nucleus is the very general 

 rule ; the sympathetic cells of rabbits, hares, and guinea pigs 

 forming an exception ; many sympathetic cells with two or, 

 occasionally, even three nuclei being here found. 



3) The neuraxes of sympathetic cells may be medullated 

 throughout, medullated for only a portion of the process, or 

 non-medullated throughout ; the medullary sheath, if present, 

 forms a relatively thin layer, thinner than in the small medul- 

 lated cerebro-spinal fibers. (The above statements are taken 

 from Kolliker's writings.) 



The neuraxes of sympathetic neurons have one or the other 

 of the following distributions : 



a) To involuntary smooth muscle or heart muscle. 



b) To glandular tissues. 



c) To other sympathetic ganglia {1). 



d) To the spinal ganglia. 



In the special lectures above alluded to, the writer has dis- 

 cussed, somewhat at length, each of the above possible modes 

 of termination of the neuraxes of sympathetic neurons, consid- 

 ering also the literature bearing on this subject. It may here 

 suffice to add that Arnstein (46) has recently traced, and pic- 

 tured the neuraxis of a sympathetic neuron ending in smooth 

 muscle tissue ; the writer has traced small branches of non- 

 medullated fibers from some of the small ganglia found in the 

 cat's auricle to their ending on heart muscle, and also the 

 neuraxes of sympathetic neurons of the sublingual ganglion 

 (Langley) to the epilamellar plexus surrounding alveoli of the 

 gland of the same name ; from Dogiel's (40) work, some of 



