Mar. 24,1923 
Anatomical Studies on Potato-Wart 
967 
of the fungus with reactive host cells is sufficient to initiate new growth. 
But the same parasite in the subsequent development of the new organ 
acts as inhibitor and modifier and thus alters the appearance of the new 
structure completely. Early developmental studies and the comparative 
ease with which the pathogene is identified have left no doubt that the 
wart, as a whole, is normal host tissue and that only the peripheral 
regions contain typical traumatic cells. An analogous case is presented by 
Dr. E. F. Smith (9). The growth resulting from inoculation is composed of 
normal host tissue and not of parasitized cells, as viewed by Levine (7). 
The present impossibility of demonstrating the crowngall pathogene in 
the tissues, however, gives only presumptive evidence, but a considera¬ 
tion of the reaction of host and parasite in case of the wart of potato 
should give, if analogy be worth anything, a strong support to the theory 
defended by Doctor Smith. 
The wart can be considered a foliar branch system. The existence of 
various types of warts seems to be bound up with the relative suscepti¬ 
bility of the host, the nature and extent of the primary infection, and 
such factors as tend to modify plant growth in general. 
LITERATURE CITED 
(1) Artschwager, Ernst F. 
1918. ANATOMY OP THE POTATO PLANT, WITH SPECIAL REFERENCE TO THE ON¬ 
TOGENY OP the vascular system. In Jour. Agi*. Research, v. 14, p. 
221-252, 4 fig., pi. 27-47. Literature cited, p. 251-252. 
(2) - 
1920. pathological anatomy OP potato blackleg. In Jour. Agr. Research, 
v. 20, p. 325-330, 1 fig., pi. 57-58. Literature cited, p. 330. 
(3) Bally, Walter. 
1911. cytologische studien an chyTridineEN. In Jahrb. Wiss. Bot. [Pring- 
sheim], Bd. 50, p. 95-156, 6 fig., pi. 1-5. 
(4) Curtis, K. M. 
1921. the life-history and cytology op synchytrium endobioticum 
(SCHILB.), PERC., THE CAUSE OP WART DISEASE IN POTATO. In Phil. 
Trans. Roy. Soc. London, ser. B., v. 210, p. 409-478, 1 fig., pi. 12-16. 
Literature, p. 462-464. 
(5) GiEsenhagen, K. 
1892. UEBER HEXENBESEN AN TROPISCHEN FARNEN. In Flora, Bd. 76, p. 
130- 156, pi. 12-13. 
(6) Johnson, Thomas. 
1909. CHRYSOPHLYCTIS ENDOBIOTICA, SCHILB. (POTATO-WART OR BLACK SCAB), 
and OTHER chytridiacEae. In Sci. Proc. Roy. Dublin Soc., v. 12, p. 
131- 144, pi. 9-11. List of authorities quoted in the text, p. 144. 
(7) Levine, Michael. 
1919. STUDIES ON PLANT CANCERS. I. THE MECHANISM OP THE FORMATION OP 
THE LEAFY crown gall. In Torrey Bot. Club, v. 46, p. 447-452, pi. 
17-18. 
(8) Percival, John. 
1909. POTATO-WART DISEASE: THE LIFE HISTORY AND CYTOLOGY OP SYNCHY¬ 
TRIUM endobioticum (schilb.) PERCL. In Centbl. Bakt. [etc.] Bd. 25, 
. p. 440-447, 3 pi. Literature, p. 445“446. 
(9) Smith, Erwin F. 
1921. EFFECT OP CROWNGALL INOCULATIONS ON BRYOPHYLLUM. In Jour. Agr. 
Research, v. 21, p. 593-598, pi. 101-110. 
