Clover Sickness. 
233 
basis for the mangel crop. Nitrate of soda, potash, and salt 
also give good results. The possibility of growing mangels 
continuously on the same land without injuring the tilth of the 
soil or the health of the crop is demonstrated. 
The recent abolition of the Continental sugar bounties has 
drawn renewed attention to the possibility of growing sugar 
beet in this country and of establishing sugar beet manufactories. 
Those who require scientific data as to the actual results 
obtainable from the cultivation of sugar beet over a series 
of years may turn to the record of the Rothamsted sugar 
beet experiments for the years 1871-1875 and 1898-1901. 
Other experiments have been made by practical cultivators in 
different parts of the country during recent years, all tending 
to prove the possibility of growing roots with a sufficient 
percentage of sugar for manufacturing purposes and even equal 
in this respect to Continental sugar beet. It is noteworthy that 
in the earlier Rothamsted experiments the percentage of sugar 
in the best roots did not exceed 13*08, whereas in the latter it 
reached 14*11. A sugar percentage of from 15 to 17 has within 
recent years been recorded under favourable conditions of soil 
and climate in Great Britain. 
Were it for nothing else, the Rothamsted experiments would 
be remarkable for their elucidation of the problem as to the 
sources of nitrogen in the soil and the part played by 
leguminous plants in the fixation of nitrogen from the air. But 
other problems have been investigated in connection with the 
growth of leguminous crops, and the origin of and cure for 
“clover sickness” is certainly one of the most practically 
important. The nature of this disease is still a matter of con- 
troversy, for whilst agricultural botanists ascribe it to the action 
of a fungus (, Sclerotinia ciborioides Relnn), Mr. Hall’s interpre- 
tation of the results of the Rothamsted experiments will not allow 
that this fungus is the determining cause of the disease, and he 
remarks that although in many cases it is the direct cause of 
the death of the clover plants, it is not yet understood why 
plants on “ clover sick ” land alone succumb to the infection. 
Important practical lessons are also derivable from the 
rotation experiments, and from the experiments as to the 
manurial requirements of grass land which were recently the 
subject of an article by Mr. Hall in this Journal. 
The interest of the book is enhanced by the reproduction, 
with portraits, of the biographical notices of the founders of 
the experiments, which were written by Mr. R. Warington, 
F.R.S., for the Royal Society ; and its value as a work of reference 
by the short summaries of the practical conclusions inserted 
at the end of each chapter ; by the list of references to detailed 
articles (including the numerous memoirs by Lawes and Gilbert 
