258 
are stained black, and the nucleus cannot be distinguished. At the 
base of the organ is seen a nerve consisting of some ten or twenty 
medullated nerve fibres, which evidently break up into a number of 
branches outside the basement membrane. Between the black sensory 
cells may be seen here and there very fine dark lines, sometimes 
branching, often passing nearly to the surface of the organ, and 
appearing like nerve fibrillations; but the exact relations of these fine 
fibrillations to the nerve fibres at the base of the organ could not be 
satisfactorily determined by this method. Sections cut in a plane 
tangential to the surface of the body, that is, in a plane parallel to 
the surface of the sense organs, showed distinctly the cut ends of the 
black sensory cells separated by considerable intervals, in which were 
to be seen in transverse sections the slender, upward prolongations of 
the supporting cells. Here and there in these intervals, in proximity 
to or in apposition with the sides of the sensory cells, were minute 
black points, evidently the transverse sections of the nerve fibrillations 
above mentioned. 
A second series of preparations, made from material fixed in a 
saturated aqueous solution of corrosive sublimate plus one per cent 
acetic acid, and stained with Eariicn’s haematoxylin or with HEIDEN- 
HAIN’s iron-haematoxylin, demonstrated the existence of a large basal 
nucleus in each of the sensory cells. These nuclei lie in a plane 
parallel to the basement membrane and midway between it and the 
free surface of the organ. The terminal bristles were evident, as were 
most of the other features enumerated above. 
A third series of preparations was made by Gotal’s rapid (chrom- 
osmic) method, and some interesting facts were observed in relation 
to the free nerve terminations in the epithelium generally, and 
especially in the scattered sensory organs of the skin; but the nerves 
entering the sense organs of the lateral line were not impregnated, 
although many trials of this process were made. In this respect the 
writer’s experience was like that of Rerzıus (92). LENKOSSER (92), 
too, says that these nerve fibres are very difficult to impregnate. 
A fourth series of preparations was made by injecting the sub- 
vertebral vessels of the caudal region with a stain made by dissolving 
0,1 g “methylen blue BX” S. MAYER (GRÜBLER) in 15 ccm of normal 
(0,75°/,) salt solution. The same stain was also injected hypodermic- 
ally at points about two centimeters apart along the lateral line. At 
the end of fifty-five minutes the fish died. ' Strips of skin and sub- 
jacent tissue, including the canals, were then cut out and immersed 
