FINGER AND TOE. 351 



This measure will not, however, be successful if charlock or 
other cruciferous weeds are not kept thoroughly in check, as 
they contract the disease and pollute the ground exactly in 
the same way as a crop of turnips. 
Finger and Toe is not only easily transmitted from a 
diseased crop to another cruciferous crop that may follow on 
the same field, but it is also a perfectly simple matter to 
establish the disease on a healthy field if diseased turnips or 
diseased soil be spread upon it. ‘Infection in this way,” 
Professor Somerville says, “‘ takes place much more frequently 
than farmers are generally aware. Diseased roots, for 
instance, may be carted from one field and consumed upon 
another, and if this second field comes under turnips, or 
similar crops, within the next few years the crop is practically 
certain to be more or less attacked. Spread of the disease 
by means of infected soil may take place in a variety of ways. 
If a crop is diseased only in certain patches, very often the 
headlands soil from these places may be carried on agricul- 
tural implements, or on the feet of men or horses, and dropped 
at other parts of the field. In this way new centres otf 
infection are sure to be created. Then, again, the soil that 
accumulates in the root shed may be carted out and spread 
on an arable field, with disastrous results. Farmyard 
manure is often accountable for the spread of the disease. 
When turnips or swedes are being consumed by cattle in the 
yards, bits of the roots and the cleanings of the troughs not 
infrequently get amongst the litter, and if the crop has been 
at all diseased the manure is thereby infected. Should the 
manure be afterwards conveyed to arable land, and much of 
it is used directly for dressing cruciferous crops, it cannot fail 
to prejudicially affect the health of the plants.” 
It is well known that Finger and Toe never appears in crops 
growing on soil which holds a high percentage of lime, and 
it has iong been the practice to treat infected land with 
dressings of lime, usually applied in the autumn of the year 
immediately preceding the season when a turnip crop is to 
be grown or a year earlier. During the past six years 
Professor Somerville has carried out a series of experiments 
- to ascertain whether the disease could not be more satisfac- 
