No. I.] SYMPATHETIC GANGLIA OF VERTEBRATES. 67 



(39), and Lenhossek (29); and with the methylene blue method 

 by Aronson (19) and Dogiel (40, 41). Each writer has m turn 

 reviewed the work of those who have preceded him, to such 

 an extent that a special review of the literature seems here 

 uncalled for. The observations made by others will thus be 

 considered in giving my own results. 



The observations here to be recorded cover a period of now 

 nearly three years ; in the earlier portion of this work the 

 Golgi method was to some extent used, but in the last two 

 years the intra-vitam methylene method alone was used, and 

 the results to be recorded pertain exclusively to observations 

 made with it. 



The animals investigated varied in age from such as were 

 two or three weeks old to such as were full grown. The meth- 

 ylene blue solution was injected through the jugular or femoral 

 vein, usually the former ; the quantity varying with the size of 

 the animal. 



The ganglia studied were the superior and inferior cervical, 

 the stellate ganglion, the smaller ganglia of the chain, and 

 many of the peripheral ganglia. These were exposed forty-five 

 minutes to an hour after the injection; were fixed in ammo- 

 nium molybdate and studied in sections, either stained only 

 in the methylene blue or double-stained in this dye and alum 

 carmine. 



Some of the results here to be given were known to me before 

 Dogiel's (40) article (from which I shall quote freely and to 

 some extent follow) reached me. It seems, nevertheless, advis- 

 able to give them, for, notwithstanding the fact that we have 

 both used the methylene blue method in our investigations, 

 Dogiel's observations were made on tissues stained on the slide 

 and fixed in ammonium picrate ; and, furthermore, his observa- 

 tions pertain more particularly to the smaller peripheral ganglia 

 (wall of the gall bladder and so forth), where it is possible to 

 study the ganglia as a whole. He was in this way able to obtain 

 preparations of sympathetic neurons, which for completeness 

 of staining, judging from his pictures, seem not to have been 

 equaled. My own observations, as above stated, were made 

 on sections, usually double-stained in alum carmine ; and while 



