Chapter 13. 
INJURIOUS ANIMALS OTHER THAN INSECTS. 
Injurious and beneficial Animals. Birds and the need for 
scientific investigation with reference to their food at different 
Seasons of the year. Eelworms and more especially the Stem 
Eelworm and the Knot Root Eelworm. Pulmonate Molluscs 
(Snails and Slugs). The Black Currant Gall Mite, 
All who engage in agricultural or horticultural pur- 
suits sooner or later have to concern themselves with some 
of the forms of animal life which are associated with their 
plants. Very frequently certain of these animals - are 
directly injurious to the operations of man, but there are 
others which, on the contrary, are distinctly beneficial in 
their effects. It is, therefore, a matter of considerable 
importance to be able to discriminate between these two 
classes, for it is obviously bad policy to devote time and 
money in destroying organisms which are beneficial in 
their action. The animal kingdom comprises a_ vast 
assemblage of different forms, but fortunately for our 
present purpose we need only concern ourselves with a 
relatively small proportion of their number. These in- 
clude certain birds, species of Nematodes or Eelworms, 
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