259 
in the same solution of methylen blue for a few minutes, after which 
they were exposed to the air and kept slightly moistened with the 
staining fluid for one hour. They were then fixed in BETHE’s am- 
monium-molybdate fluid for three hours, washed in water for an hour 
and a half, dehydrated, cleared in xylol, and imbedded in paraffine. 
During the processes of fixing in BErTHE’s fluid, washing and de- 
hydrating, the fluids and material were kept at a temperature of 
HE. 
Sections cut as in the first series showed very distinctly and 
beautifully the relation of the nerve fibres to the cellular structure 
of the organ. It is as follows: — At the base of the sensory organs 
outside the basement membrane the nerve fibres lose their medullary 
sheath. They then branch repeatedly, at the same time spreading out 
over the whole bottom and sides of the organ, crossing each other in 
every conceivable direction. Anastomoses between these branches pos- 
sibly exist, but none were observed. ‘These branches pierce the base- 
ment membrane in many places and rise, still branching, to the bases 
of the sensory cells. Around the bases of these cells some of the fine 
nerve fibres intertwine in a kind of basket-like network, from which 
fibrillations rise still higher, nearly to the free border of the organ. 
Other fibres take no part in this basket-like plexus, but extend up- 
ward, still branching, in close apposition to the sensory cells. 
The sensory cells in these preparations are stained dark blue, 
like the axis cylinders and nerve fibrillations. They are very clearly 
seen to terminate in bristles, which are a little less deeply stained 
than the cytoplasm; but at the junction between the bristle and the 
body of the cell there is a narrow zone which is stained even darker 
blue than the nucleus itself. 
From the peculiar position and arrangement of these sensory cells 
and from their relations to the fibrillations of the nerves reaching the 
organ, one might infer that they have a special nervous function to 
perform. This view is strenghtened by their peculiar reaction to both 
the vom Rarn’s fixative and the methylen-blue stain; the conclusion 
would therefore seem inevitable, that they are in the strictest sense 
nerve elements conforming to the type of anaxionic neurons. 
Papers cited. 
"92. v. Lenuosstx, M., Die Nervenendigungen in den Endknospen der 
Mundschleimhaut der Fische. Verhandl. Naturf. Ges, Basel, Bd. 10, 
p. 92—100. Taf. 11, 
