NERVE CUTTING IN AMIURUS 373 
that is, there was better general condition and absolutely no 
mortality. 
The nerves to the two dorsal and the two lateral barbels in 
over one hundred fishes were cut in the manner indicated, and in 
fifty others as much as possible of the peripheral stump was 
pulled out through the cut and removed. This second set of 
experiments was for the purpose of determining whether the 
mass of degenerating tissue might possibly have an effect on the 
time of disappearance of the taste buds—naturally, the individual 
branches to the buds still remained—but there was no difference 
in the behavior in the two sets of fish. Barbels were removed 
daily and prepared by various methods for histological study. 
Heidenhain’s (714) special osmic-acetic-sublimate mixture, 
which gave him his best fixation of the dog’s tongue, was only 
fairly successful for the taste buds of Amiurus, but was excellent 
for other structures, e.g., wandering pigment cells and nerves, 
chiefly on account of the presence of osmic acid. <A rapid fixing 
agent compounded by Mr. A. W. L. Bray gave especially good 
preparations of the buds, though other tissues were slightly 
shrunken. This fluid consisted of equal parts each of absolute 
alcohol, formalin, and glacial acetic acid; the mixture was then 
saturated with corrosive sublimate and used for thirty minutes 
at a temperature of 50° to 60°C. But most satisfactory of all 
was formol-Zenker (4 to 10 ec. formalin added to Zenker’s fluid 
without acetic acid immediately before using). Among various 
stains, safranin, especially after Bray’s fluid and Delafield’s 
haematoxylin counterstained with eosin, proved to be very good, 
but best of all was Heidenhain’s iron-haematoxylin, either with- 
out counterstain or with eosin or orange G. Retzius (712) found 
that Zenker’s fluid followed by Heidenhain’s iron-haematoxylin 
gave him the best results with the dog’s tongue. Various silver 
methods were tried, the most successful being Bielschowsky’s. 
For nerves alone osmic acid was used, both teased preparations 
and sections being made. 
The majority of the work was done at Woods Hole, Massa- 
chusetts, where the average temperature of the water in the 
laboratory was about 22°C. After the operation of nerve cutting 
