4 BULLETIN 109, U. S. DEPARTMENT OF AGRICULTURE. 
MOLDS IN TRAGACANTH GUM. 
Tragacanth gum is usually bought in considerable quantities for use 
in the larger factories, and, if the samples obtained in this investiga- 
tion from several such sources were representative, the highest grades 
of the gum are not used. It was thought possible that these gums 
themselves might be carriers of molds, and several samples were set 
‘away in sterile Petri dishes to which a small quantity of sterile dis- 
tilled water was added. These cultures, like others to be described, 
-when not under observation were kept in a dark chamber in which 
the temperature varied between 21.5° and 25° C. In three days all 
the samples showed an abundant growth of molds, which began to 
develop fruiting stages on the fourth day. For further study, cul- 
tures were transferred to a medium containing one-half of 1 per cent 
sodium chlorid, 1 per cent peptone, 1 per cent beef broth, and +10 
points acidity. Other cultures were also prepared on sterilized 
tragacanth gum, partly prepared on a thick paste and partly on a 
thinner paste. 
_ Cultures on beef agar and peptone flourished and yielded a variety 
of organisms, which were turned over for identification to Mrs. Flora 
W. Patterson, Mycologist of the Bureau of Plant Industry. Four 
forms appeared with great regularity. Most conspicuous and quick- 
est in growth were (1) Rhizoporus nigricans Ehren., a large organ- 
ism forming large, loose, conspicuous hyphal masses; (2) Mucor 
“racemosus Fres. var. brunneus Morini, a smaller organism rapidly 
Torming a loose, white mass of hyphe; and (3) Penicilleum sp., a 
somewhat slower organism in point of development, marked by its 
white round-headed eonidiophores. This organism in the early 
stages was striking by reason of its brilliant whiteness, but as the 
cultures grew older the more usual bluish color appeared. The last 
common form was (4) Aspergillus candidus Link, a very small mold, 
‘characterized by its slower growth, its dingy site color, and ae 
appearance in mixed cultures as a minute undergrowth among the 
above-mentioned larger organisms. No attempt was made to carry 
out a further study of these organisms. It seemed clear, however, 
that the Aspergillus was more at home on the tragacanth medium 
than on the beef agar and peptone as here offered. 
MOLDS ON WRAPPER LEAF. 
As it seemed very probable that the wrapper leaves, like most 
other free surfaces, might give lodgment to spores of molds and 
thus become agents of infection, it was thought desirable to see what 
molds could be cultivated from them. Accordingly, cultures in the 
media previously described were prepared from the washings ob- 
tained by rinsing the surfaces of wrapper leaves with sterile water. 
Several organisms were obtained in small quantities, and Mrs. Pat- 
