22 HUBER. [Vol. XVI. 



with snow or ice. The solution is best made some time before 

 the injection, so that it may be properly cooled before using. 

 In the fixative the tissues remain three to five hours. They 

 are then washed in distilled water for about one hour and de- 

 hydrated and hardened in absolute alcohol, placed in xylol and 

 imbedded in paraffin. As a rule, the ganglia were cut into 

 serial sections, fixed to slide with the albumen fixative, and 

 mounted in Canada balsam ; other series were double-stained 

 in alum carmine before mounting. 



My experience as to the durability of preparations made in 

 this way has not been the most satisfactory, although, as a rule, 

 they have kept without fading for several months. Some of 

 the sections (ganglia of Amphibia) have been well preserved for 

 over two years, and are only now beginning to show signs of 

 fading ; others (sections of sympathetic ganglia of the chicken) 

 began to fade at the end of several weeks. My experience 

 would go to show that sections double-stained in alum car- 

 mine keep better than such as are stained only in the meth- 

 ylene blue. Why some sections should seem to fade more 

 readily than others I am unable to say ; it would seem, how- 

 ever, ' that sections thoroughly dehydrated and thoroughly 

 washed in oil of bergamot and xylol fade less quickly than 

 those where these precautions are not taken. Sections exposed 

 to light fade more readily than those kept in the dark. Bethe 

 (2) in discussing this phase of the matter says : " Die Halt- 

 barkeit der Praparate, die mit der einfachen Fixation hergestellt 

 sind, ist keine unbedingte. Sehr dicke Praparate zeigen oft 

 schon nach zwei bis drei Monaten zuerst ein Dunkelwerden des 

 Canadabalsams, auf den Triibung des Protoplasmas und Diffus- 

 werden der Farbung folgt." " Schnitte halten sich besser, 

 vielleicht deswegen, weil hier der Ueberschuss von Ammonium- 

 molybdat, von dem in Verbindung mit Resten von Alkohol die 

 Zerstorung auszugehen scheint, besser ausgewaschen wird." 



In attempting to stain the sympathetic ganglia of fishes by 

 injecting methylene blue into the circulation (through the cau- 

 dal vein), it was found that the loose adipose tissue in the gill 

 region, in front of the vertebral column, by the removal of 

 which a number of small ganglia were brought to view, stained 



