IOWA ACADEMY OF SCIENCE 
183 
The data was as follows : 
Pot 
Dilution 
Bacteria 
Molds 
165 
1-10 
Many 
Many 
Many 
Few 
Many 
Many 
Many 
Many 
165. 
1-100. . .... 
166 
1-10. ...... 
166. 
1-100 
167. 
1-10 
167 
1-100 ...... 
Few 
168. 
1-10 
168 
1-100 
Few 
This shows that none of the pots were sterile but that the molds 
were more numerous than the bacteria. There was apparently only 
one species of bacteria but three kinds of mold. 
These pots were sterilized over again leaving them a longer time 
in the autoclave. The seeds were sterilized by leaving them 2!/2 
hours in the corrosive sublimate solution. Planted November 
27th. This time the clover on the unsterilized pots was attacked 
and killed by mold while the plants on the sterilized pots grew 
slender and sickly and finally died. Thus nothing was learned from 
these two experiments except that clover was a difficult crop to 
grow under these conditions. 
As clover was found to be so unsuitable, it was decided to try 
wheat, as the probabilities are that the relation between wheat 
and the bacteria is very nearly the same as that between clover and 
bacteria. 
The same soil was used. The series was as follows: 
Pot 401 and 402 checks. 
Pot 403 and 404 leachings of manure. 
Pot 405 and 406 sterilized. 
Pot 407 and 408 leachings added and sterilized. 
The wheat for the seeding was sterilized with corrosive sub- 
limate for two hours, and then washed several times with sterile 
water. The pots with ,/the soil in them were sterilized in the auto- 
clave for one hour at 10 to 15 pounds pressure. 4 inch pots were 
used and one was put under each bell jar. 5 seeds were planted 
in each pot one-fourth inch deep on January 11, 1907. None of 
the wheat sprouted, evidently being killed by the corrosive sub- 
limate. 
The series was planted again February 4th. The soil was re- 
sterilized, and the seeds kept only twenty minutes in the saturated 
solution of corrosive sublimate. Only one seed in this series grew. 
