336 
Anbury, Club-root, or Finger and Toe. 
X:iooo' 
many independent observers have confirmed his conclusions. 
He found that anbury was due to an attack of a parasitic fungus 
which lived within the tissues of the roots. The nature of the 
disease will best be understood by the reader if the history of 
the parasite is traced from the germination of the seed, or more 
properly the spore, until the spores are reproduced. 
The spore (fig. 1) 1 is a very minute, perfectly round and smooth 
ball. It is so small that it is difficult, if not impossible, to realise 
its size. Some help towards apprehending its 
minuteness may be obtained if we consider the 
number required to measure an inch, though 
we must use numbers that convey little mean- 
ing except vastness. Sixteen thousand laid 
touching each other in a straight line would 
measure only an inch; it requires 250 millions 
Fn;. i. — spores”of the to cover a square inch, and no less than four 
WoTimes masnified billions (4,000,000,000,000) to fill up the 
measure of a cubic inch. Singly they appear 
colourless, but when aggregated in the cells of the diseased 
turnip where they are produced they exhibit a yellowish tint, 
which in contrast with the normal tissues gives a section of the 
swollen part of the root a clouded appearance. 
The spore consists of a particle of a somewhat uniform jelly- 
like substance called protoplasm enclosed in a delicate little 
round bag or cell. This corresponds to the seed stage of the 
life of a higher plant, and, like the seed of the pea or the turnip, 
the spore remains through the winter without germiuating. 
It passes this period in the diseased turnip in which it is pro- 
duced, or if that is destroyed it rests in the earth or the dung 
heap, or if the turnip be not so far destroyed that it is eaten by 
stock it passes through the intestinal canal of the animal with- 
out injury. 
The spore germinates in the spring. The delicate covering 
bursts, and permits the passage out of the jelly-like protoplasm, 
and the round bag is left empty (fig. 2). There is no difficulty in 
observing this operation under the microscope ; the spore being 
placed in a little tvater on a piece of glass will, at a suitable 
temperature, gradually push out the contents. The young plant, 
if we may call it so, is at this stage only a minute bit of un- 
protected jelly, resembling in its structure and actions the very 
simple animal — familiar to the student of the microscope in putrid 
infusions — which is named an amoeba. Like this animal it is 
1 This and the other illustrations are reproduced from the text-book 
Elements of Agriculture, by W. Fream, LL.D., 4th edition, 1892, p. 308, 
London : John Murray. 
