Journal of Agricultural Research 
Vol. XXVII, No. y 
166 
normal metabolism of the resting root. Since breakdown is, to all appear¬ 
ances, correlated with metabolic changes in the resting root, it might be 
possible to find a satisfactory explanation on a purely mechanical basis 
by ascertaining the chemical composition of susceptible and resistant 
fleshy roots and noting the changes which take place under various 
conditions of storage. From such evidence it may be possible to deter¬ 
mine the origin of the trouble, or at least to discover significant correla¬ 
tions which may point to the solution of the problem. 
SUMMARY 
The edible structure of Ipomoea batatas is a thickened root. Its 
peculiar anomalous structure is due partly to the action of a primary 
cambium, partly to the development of secondary cambiums and their 
products. 
The cells of the interstitial parenchyma of certain of the varieties 
break down in storage, causing the formation of polyhedral chambers 
lined with the cottony debris of the disintegrated tissue. 
LITERATURE CITED 
(1) Bary, Anton de. 
1884. COMPARATIVE ANATOMY OF THE VEGETATIVE ORGANS OF THE PHANER¬ 
OGAMS and FERNS, xvi, 659 p., 241 fig. Oxford. 
(2) Harter, L. L., Lauritzen, J. I., and Weimer, J. L. 
1923. internal breakdown of sweet potatoes. In Phytopathology, 
v. 13, p. 146-147. 
(3) Kamerling, Z. 
1914. SIND DIE KNOLLEN VON BATATAS EDULIS CHOISY WURZELN ODER 
STENGEL? In Ber. Deut. Bot. Gesell., Bd. 32, p. 352-360, 8 fig. 
Bibliographical footnotes. 
(4) McCormick, Florence A. 
1916. NOTES ON THE ANATOMY OF THE YOUNG TUBER OF IPOMOEA BATATAS 
LAM. In Bot. Gaz., v. 61, p. 388-398, 8 fig. Literature cited, 
, x o „ p- 397-398- 
(5) Schmitz, F. 
1875. UBER DIE ANATOMISCHE STRUCTUR DER PERENNIRENDEN CONVOLVU- 
laceen-wurzeln. In Bot. Ztg., Jahrg. 33, p. 677-679, 686-690. 
(6) Turpin, P. J. F. 
1830. Memoire sur l’organization interieure ET exterieurE des 
TUBERCULES DU SOLANUM TUBEROSUM ET DE L’HELIANTHUS TUBERO- 
sus. In Mem. Mus. d’Hist. Nat. [Paris], t. 19, p.1-56, 5 pi. 
(7) Tuyihusa, V. 
1914. ARE the BULBS OF BATATAS EDULIS CHOISY ROOTS OR STEMS? (In 
Japanese.) In Bot. Mag. [Tokyo], v. 28, p. 475. 
