152 GEORGE E. NICHOLLS 
the sloping surface there. It was killed at 6.30 p.m., August 22. 
Duration of experiment 18 days 23 hours. 
The severed (hinder) portion of the terminal filament had not 
markedly disintegrated but the short length of Reissner’s fiber sepa- 
rated by the incision has altogether disappeared. There is visible some 
disorganization of the terminal filament in front of the lesion, but a 
little in front of the point where the cut was made the lumen of the 
central canal seems to have been widened somewhat, perhaps, to form 
a secondary sinus terminalis. Stretching backwards to this point, 
there is seen a flimsy wrinkled and fibrillate structure which is, I be- 
lieve, the expanded hinder end of Reissner’s fiber. 
34. The incision, which was made at noon, August 14, was followed 
within a quarter of an hour, by a distinct reaction (fig. 4). This con- 
tinued and was well marked at 3 p.m. when the specimen was killed. 
Duration of experiment 3 hours. 
In front of the region where the experimental incision was made, 
the fiber is found retracted and swollen with some spiral twisting. 
Behind the point of injury the fiber is markedly swollen and appears 
fibrillar. 
33. The incision was made at 12.05 p.m., August 14, and by 1 p.m. a 
slight reaction had appeared, but for the greater part of the day, the 
animal rested with the tail turned over upon its side. The whole 
body was strongly curved. During the following day this same atti- 
tude was largely maintained but at times the tail was seen to be lifted 
considerably. The specimen was killed at 8.45 p.m., August 15, the 
duration of the experiment thus being 1 day 82 hours. 
Reissner’s fiber is found swollen, retracted forward from the region 
of the experimental incision and, at the free end, is slightly spirally 
wound. ‘Traced forwardly this spiral becomes a very open one and the 
fiber passes into a comparatively straight course. It probably repre- 
sents a stage in unwinding. 
43. The incision was made at 11.20 a.m., August 18, and was quickly 
followed by the usual reaction, the head being well raised. By noon 
the tail, also, was well lifted and the head still further raised. At 
7.15 p.m. when the specimen was killed, the reaction appeared less 
pronounced. Duration of experiment 8 hours. 
In front of the lesion, Reissner’s fiber had disappeared entirely from 
the length of tail examined. Behind the incision also, the fiber has 
evidently contracted, the canal being devoid of fiber nor can the con- 
tracted piece be certainly recognized. 
44, The incision was made at 11.45 a.m., August 18, but no reaction 
appeared either upon this or the following day. The specimen was 
killed at 8 p.m., August 19. Duration of experiment 1 day 81 hours. 
The fiber though severed has apparently been gripped by the ad- 
pression of the walls of the terminal filament and there has been no 
retraction of the fiber in either direction (fig. 30). 
