702 
Journal of Agricultural Research voi. xxm. No. * 
The writer did not have an opportunity to study the original imported 
seed until well into the winter. Then repeated attempts were made to 
isolate the organism, without success. H. E. Stevens, of the Florida 
Experiment Station, however, working on this phase of the problem 
earlier in the fall, succeeded in isolating the causal organism from samples 
of the imported seed. (Letter of May 9, 1919.) He planted them on 
sterilized sand, and on a few seed the gray mold developed. Later, the 
writer made a final examination of some of the Bombay seed in one of 
the original bags, and a single small sclerotium was found. This was 
planted on a plate of moist sand under a bell jar, and eventually an 
apothecium, the perfect stage of the fungus, developed. 
Letters written to pathologists in India were at first not completely 
satisfactory in leading to the solution of the origin of the fungus, the 
earlier replies stating that it was not known there. A subsequent letter 
from J. F. Dastur, dated February 15, 1921, brought word that the 
disease had been found in Mysore, South India, and was under investi¬ 
gation by one of the plant pathologists. More recently (Aug. 13, 1921) a 
culture was received from India. This culture contained only conidia, 
which in form and size appeared to be identical with the American form. 
Later appearances in culture, however, throw some doubt on its identity 
with our organism. In oatmeal agar the sclerotia are not so abundant, 
conidia are fewer, conidiophores not so definitely dichotomous, and the 
development of white mycelium is greater. No perfect stage has devel¬ 
oped for final comparison. In spite of this possible discrepancy, the 
evidence is very strong that the pathogene came from India to this 
country along with the seed. The fact that it has been discovered there 
only recently, if at all, is especially interesting, in that it appears to 
present one more case of an introduced parasitic fungus being more 
serious in its new habitat than in its old. 
INOCULATION EXPERIMENTS 
Field observations made the first year, in the course of surveys in the 
South, made it clear that for successful inoculations a prime requisite 
would be moisture. After a few preliminary inoculations it became evi¬ 
dent that an abundance of moisture was necessary not only for primary 
infection to take place but for the disease to develop in the host, even 
after the fungus had penetrated into the interior. The first inoculations 
were made on seedlings by applying the fungus along with some of the 
culture medium to different parts of the plant, without injury, and then 
covering with a bell jar. This resulted almost invariably in success. 
Within 24 hours positive infections became evident. Plate 8, B, shows 
distinct lesions on a young seedling, produced by artificial inoculation 
in the Cornell University plant pathological greenhouse, in January, 1919. 
Other inoculations made at the same time consisted in the application of 
conidia to young growing leaves. These were successful unless the plants 
became dry during the incubation period of the fungus. Material of 
plants, particularly leaves, thus infected, was fixed for later histological 
work to determine the manner of penetration of the fungus into the host. 
Castor bean seeds were also sterilized in calcium hypochlorite, after the 
method described by Wilson (23), and planted in large 10-inch tubes of 
synthetic agar, with the result that about a dozen castor bean plants in 
pure culture were secured* Inoculations were later made on these with 
resulting rapid infections. 
