392 J. M. D. OLMSTED 
9. New barbels regenerate where old ones are removed, and 
become fully equipped with taste buds by the time they have 
reached a length of 5 mm. 
10. Stubs of normal barbels regenerate new ends with normal 
buds, but barbels whose nerves have been cut do not regenerate 
at all. 
11. The presence of taste buds in a barbel is dependent on the 
presence of a normal nerve in the barbel, since the taste buds 
degenerate and disappear when the nerve degenerates and reap- 
pear when the nerve has regenerated. Likewise, the power of 
a barbel as a whole to regenerate a missing tip is dependent upon 
the presence of a normal nerve in that barbel. 
12. The theory that certain chemical substances of the nature 
of hormones are given out by the nerves, and that such sub- 
stances are necessary to the existence of taste buds and also for 
regeneration of the barbel as a whole, accounts for all the pheno- 
mena of degeneration and regeneration in the barbel of Amiurus. 
BIBLIOGRAPHY 
ARNSTEIN, C. 1893 Die Nervenendigungen in den Schmeckbechern der Sauger. 
Arch. f. mikr. Anat., Bd. 41, S. 195-218. 
Baainsky, B. 1893 Ueber das Verhalten von Nervenendorganen nach Durch- 
schneidung der zugehérigen Nerven. Arch. f. Anat. u. Physiol., 
physiol. Abth., Jahrg. 1898, S. 559-560. 
1894 Ueber das Verhalten von Nervenendorganen nach Durchschnei- 
dung der zugehérigen Nerven. Arch. fiir path. Anat. u. Physiol., Bd. 
137, S. 389-404. . 
Drascu, O. 1887 Untersuchungen iiber die Papillae foliatae et circumvallatae 
des Kaninchen und Feldhasen. Abhand. Sachs. Gesellsch. Wissensch., — 
Bd. 24, S. 229-252. 
Epner, V., von 1899 A Koelliker’s Handbuch der Gewebelehre des Menschen, 
Bd. 3, 402 S. 
GRABERG, J. 1899 Zur Kenntniss des celluliren Baues der Geschmacksknospen 
beim Menschen. Anat. Hefte, Arbeiten, Bd. 12, S. 337-368. 
GouprarB, A. J. 1909 The influence of the nervous system in regeneration. 
Jour. Exp. Zodl., vol. 7, pp. 643-722. 
1914 Regeneration in the annelid worm, Amphinoma pacifica, after 
removal of the central nervous system. Papers Tortugas Lab., Car- 
negie Instn., vol. 6, pp. 97-102. 
Heimennatrn, M. 1914 Uber die Sinnesfelder und die Geschmacksknospen der 
Papilla foliata des Kaninchens. Beitrige zur Teilkérpertheorie III. 
Arch. f. mikr. Anat., Bd. 85, S. 365-479. 
