BULLETIN OF THE BUSSEY INSTITUTION. 835 
he is throwing away his money, as far as accomplishing that purpose, at 
least, is concerned. The object is to prevent as much harm as possible 
from being done to the plants in which the mycelium already exists, and 
to prevent the spread of the disease to healthy plants. If we could con- 
trol the amount of moisture in the air about the time when the disease 
is likely to appear, say from the middle of July until the first of Sep- 
tember, the mycelium would not increase to any extent to cause prac- 
tically any harm. That we, unfortunately, cannot do, and all that 
remains is to drain the land thoroughly, or plant in a dry soil. It is 
difficult to understand why our farmers persist in planting potatoes in 
swamps and wet heavy soils, knowing as they do from experience that 
such plants are always the first to rot. Since the disease does not 
appear until about the first of August, it follows that the early pota- 
toes should be less likely to rot than late ones. This is found practi- 
cally to be the case, and early varieties are much to be preferred to late 
ones. Exactly what variety a farmer should plant is not a question to 
be decided by a botanist, but it. should, at any rate, be a vigorous 
grower, and ripen as early as possible, the size and marketable quali- 
ties being equal. Certain varieties seem to resist the disease better 
than others, but, as yet, we know of none which may not be attacked, 
and opinions as to exactly which varieties have the greatest resisting 
power are so contradictory that it is impossible to decide the matter. 
The views of persons having potatoes to sell for planting are, natu- 
rally, not always unprejudiced, and many farmers have theories on the 
matter in question which were evolved from their inward conscious- 
ness quite as much as deduced from accurate experiments. The Coun- 
cil of the Royal Agricultural Society of England have appointed a 
Special Committee to examine into the subject of varieties of potatoes 
which will resist the rot for three years in succession, and several vari- 
eties are being tested in twenty different places in the United Kingdom. 
Two years more must elapse before the results are fully known, and 
then we may, perhaps, expect more definite information on this impor- 
tant subject than we as yet possess. 
The precautions to be taken to prevent the extension of the disease 
will be more definitely known when the plant in which the odspores 
are produced has been discovered. At present, we cannot say with 
certainty that these are found either in clover, or in wheat, oat, or rye 
straw, and our knowledge of the subject is still too slight to warrant a 
