90 STEM EELWORMS. 
splendidly strong, especially the Red Clover. They have given during 
several months of the autumn a large amount of sheep keep, and they 
are now attracting large flights of Wood Pigeons, which, as you know, 
feed greedily on the leaf of Red Clover. 
‘* Now, why is the Clover apparently free from disease on ground 
where the Oat crop was greatly damaged from Tulip-root? By the 
way, the Oats were Black Tartarians, from which I expected a very big 
crop. About thirty years ago I lost a crop of Oats in a similar way, 
but not on the same ground.”—(T. C. 8.) 
I certainly without more information of previous details cannot say 
with certainty why the Eelworm should leave the Clover uninfested ; 
but there are two points, either of which might bear on the matter. 
One is that the Clover was in such remarkably hearty and healthy 
srowth. This is in itself a great help against injury from Kelworm 
infestation. ‘The other lies in the circumstance that although Eel- 
worms from one kind of crop subject to their infestation can pass, as 
we constantly see, to another crop similarly susceptible, yet it is 
matter of recorded observation that where they (the Tyleuchus devasta- 
triv) have lived for some generations in one kind of plant, that if 
possible they prefer continuing their infestation to that kind to 
attacking plants of a different nature. 
Some special instances of this in the case of non-infestation of 
Clover, in connection with infested Rye, are given by Dr. Ritzema 
Bos, in his work previously quoted, p. 73:—‘‘In different parts of 
Limbourg, where Clover is rarely or never cultivated, the Lylenchus 
devastatriz does not pass into this plant, or at least it is not attacked 
by the sickness even when it is sown on infested ground.” Similar 
observation is noted to have been made in some other districts, where 
Rye has been grown for years on infested fields, but Clover rarely or 
never. ‘But in countries where Clover is much more cultivated, the 
plant is not exempt from the attacks of this dangerous nematode ”’ (the 
Stem EKelworm, H. A. 0.). 
In this country we are in the latter situation ; Clover and Oats are 
constantly infesting each other to and fro, and the matter is one of 
practical interest, although in the case of Mr. Carrington Smith’s crop 
I would not without details say what was the cause of the failure. 
The Clover-sickness above referred to, which is due to presence of 
Stem Eelworms, is easily distinguishable from all other kinds of 
Clover disease, whether caused by unsuitableness of soil, insufficient 
alternation of crops, mould or fungoid attacks, maggots of the Clover 
and Pea Weevil at the roots, or other injurious circumstances, by the 
definitely deformed growths. 
In the case of Clover ‘‘stem-sickness’’ in the early part of the 
year, the circumstance of the stalks and branches being shorter and 
