108 TRANSACTIONS OF THE 
which, in reality, cause infection of plants as the smut 
spores themselves; and, by way of parenthesis, I may state 
that the common stinking smut of wheat so prevalent in 
the fields of Utah may act as the smut of corn and there is 
a possibility that these air conidia too can reach the blossom 
of wheat by means of wind and produce infection. This point 
needs investigation, and when finally settled, it may clear 
up some of the inexplainable conditions found in connection 
with the control of this disease. Brefeld himself to-day is 
working somewhat on this problem. Still further, we may 
add that the study of blossom infection has not been limited 
to the two forms already mentioned, i. e., those forms that 
produce loose smut, and such as the corn which produce 
air conidia, but has also been extended to smuts that are’ 
carried by air and by water. 
METHODS USED IN THE IVESTIGATION OF THIS PROBLEM 
OF BLOSSOM INFECTION. It may be of interest to mention 
to you in a very general way some of the methods used to 
determine blossom infection in smuts. The first difficulty 
lies in the collecting and presevation of smut spores from 
the summer in which they are produced until the following 
spring. The spores are often attacked by insects and des- 
troyed, so that their germinating capacity the following 
year has been lost. This difficulty has been overcome by 
the following method. Spore material is gathered in suf- 
ficient quantities soon after the breaking open of the spore 
masses and then kept in a dry place for approximately 
eight days. The spores are then sifted through a sieve on 
to white paper. These sieved spores are carefully put 
away in small sterilized flasks. These flasks are filled in not 
more than one-fourth to one-fifth. The neck is closed with 
sterilized paper and spores are put away into a dry cool 
place for storage through the winter. In spring, shortly 
before using them, the spores are placed in sterile water for 
a day and thrown about five or six times on a centrifugal 
sieve. The first spores thrown out are almost perfectly 
pure and cultures can be carried out in sterile nutrient solu- 
tion with scarcely any pollution at all. 
