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XV. — Oyi Purples or Ear-cockle in Wheat. 
By William Cakeuthees, F.RS., Consulting Botanist. 
PUEPLES, ear-cockle, or pepper-corn, is a disease in wheat caused 
by the attack of a minute worm. It is happily not a frequent 
disease. When it occurs it is local, and sometimes very in- 
jurious. The ear of wheat is full-grown, the seeds, in one or 
more cases, are replaced by small roundish bodies, shorter than 
the seed, and somewhat broader, and nearly black in colour. 
When one of these bodies is cut through, it is found to consist 
of a considerable thickness of dark empty cellular tissue sur- 
rounding a kernel of a white cotton-like substance. If this 
kernel be placed in water it breaks up into short, separate, 
moving threads, which are revealed by the microscope to be a 
mass of minute worms. 
The presence of these worms in the ear-cockle has been long 
known. They were first detected by Needham, in 1748. And 
they have formed the subject of special papers by Roffredi, Bauer, 
Henslow, and Davaine. More recently the group to which 
these worms belong has been studied by other naturalists, and 
large additions have been made to our knowledge of them by 
Bastian, De Max, Oerley, and others. The species that attacks 
the wheat was called Vibrio triticum by Bauer, afterwards An- 
guillula graminearum by Diesing, and is now known as Tylenchus 
Tritici of Bastian. It belongs to the order Neniatoidea, a group 
of round thread-worms which are found either parasitic on other 
animals, or living free in salt or fresh water, in moist earth, 
and on or in plants. Bastian, as the results of his investigations, 
expresses his belief that the free nematoids will be found to con- 
stitute one of the most widely diffused and universally abundant 
groups in the whole animal kingdom. In the short space of 
fifteen months he obtained from a few limited districts, no 
less than one hundred species that had not been previously 
described. 
The members of the parasitic group of these minute nematoid 
worms inhabit the bodies of animals of all kinds, man himself 
being the chosen habitat of no less than twelve species. The 
best-known of these are the Guinea-worm, common in the in- 
tertropical regions of the Old World, and Trichina spiraliSj 
which produces the disease called Trichinosis. This worm is 
known in two different conditions. In its first or immature 
condition it is found in the muscles of the pig. When a portion 
of the muscle containing the parasite is eaten by another warm- 
blooded animal, the worm multiplies rapidly, and pushing its 
way through the intestinal canal, takes possession of the muscles, 
