No. I.] SYMPATHETIC GANGLIA OF VERTEBRATES. 33 



SO deeply that after an injection a search for them was usually 

 fruitless. In fishes, therefore, it was found advisable to re- 

 move the ganglia, unstained, to a slide or watch crystal, and, 

 following Dogiel's suggestion, to stain them in a }-q^o solution 

 of methylene blue in normal salt. A portion of a ganglion thus 

 treated was usually stained in forty-five minutes to one hour, 

 the staining being controlled under the microscope. The tis- 

 sues so stained were then fixed in ammonium molybdate, the 

 further treatment being as above described. 



In attempting to stain the tissues on the slide, I have tried a 

 number of methods, which, in the hands of other investigators, 

 have given good results. I may especially mention the meth- 

 ods recommended by Lawdowsky (5). He suggests the dilution 

 of the methylene blue with one of the following solutions : 

 Blood serum, ^gg albumen, a -i-^-\-\^<^ solution of ammonium 

 chlorate, or ferrum ammonium chloratum. The successful 

 staining obtained by Lawdowsky has not been realized by me ; 

 on the contrary, results obtained with methylene blue diluted 

 in normal salt have been much more satisfactory. 



In closing the discussion of the methylene blue method, I 

 need hardly add that, even with the greatest care, negative re- 

 sults are only too frequent. Why, when this method is used 

 over and over again in exactly the same manner, in some in- 

 stances successful staining is obtained, in others only failure, 

 I am unable to say ; but such is the case. Then, of course, it 

 must be remembered that the investigator is always at a loss to 

 know whether the preparation before him tells the whole story, 

 or only a portion of it ; whether, in other words, the structure 

 before him is completely or only partially brought to view by 

 the methylene blue. 



Sympathetic Ganglia of Fishes. 



The sympathetic system of teleosts, to which subclass my 

 investigations were confined, consists of a cephalic, a trunkal, 

 and a caudal or post-anal portion, made up of a series of gan- 

 glia, united by intervening nerves into two cords lying close to 

 the vertebral column. The cephalic portion extends forward 



