INS 



INT 



not be ranked among injurious ani- 

 mals, notwithstanding the prejudices 

 of farmers and gardeners against 

 them. Without worms, the earth 

 would soon become hard, cold, inca- 

 pable of receiving moisture, or of 

 giving nourishment to roots : they 

 are, in fact, the great promoters of 

 vegetation, by boring, perforating, and 

 loosening the soil beneath, and by 

 manuring it above with their excre- 

 ment, which is thrown up into lumps 

 called worm casts. The wire-worm 

 does not belong to this tribe, but is 

 the larva of a small beetle already 

 noticed. 



" Worms of the slug kind are with- 

 out shells. There are several spe- 

 cies, all of which subsist on leaves, 

 roots, and vegetables. The most 

 common is the Liinax agrcstis, of 

 which there are several varieties inju- 

 rious to the agriculturist and garden- 

 er ; they devour the young shoots of 

 turnips, wheat, and, indeed, all kinds 

 of grain, frequently to a ruinous ex- 

 tent ; their eggs are small, round, of a 

 semipellucid whiteness, and are de- 

 posited in the earth. The methods of 

 destroying or eradicating the perfect 

 animal have been already described. 



" The shell slug {Tcslacellus mangi) 

 is a native of TenerifTe, remarkable 

 for feeding upon earth worms ; and 

 may, therefore, be beneficially intro- 

 duced into such gardens as are over- 

 stocked by that otherwise useful an- 

 imal. It is readily distinguished from 

 all other slugs by having a thin, oval 

 shell affixed to the hinder part of its 

 body. Slugs in general are easily 

 enticed by cabbage leaves, scattered 

 near such garden vegetables as they 

 appear to injure most. 



" Snails are slugs covered by a 

 shell. The two species most preju- 

 dicial to cultivated vegetables are 

 the garden snail (^Helix aspersa, Gm.), 

 and the variegated snail {Helix nemo- 

 ralis) ; both these seek the same de- 

 scription of food, and are equally in- 

 jurious as slugs, and, like them, may 

 be enticed by cabbage leaves and oth- 

 er juicy vegetable refuse." 



The most important insects are no- 

 ticed under each plant. 

 O o 



INSERTION. In botany, the di- 

 rection in which an organ, as the sta- 

 mens, is attached to the part that sus- 

 tains it. 



INSESSORES (from instdeo, I 

 sit). Birds which perch on trees. 



xCTcJlCTS . 



INSOLATION. Scorched by the 

 sun. 



INSPIRATION. In physiology, 

 the act of inhaling air. 



INSTEP OF THE HORSE. The 

 part of the hind leg reaching from the 

 ham to the pastern joint. 



INSULATION. In electricity, sur- 

 rounded by non-conducting substan- 

 ces, as glass, resin. 



INTEGERRl.MUS. With a per- 

 fect edge, or margin, in botany. 



INTEGRANT PARTS. The 

 smallest parts of a body, by the union 

 of which the mass is produced. 



INTEGUxMENT. A membranous 

 covering or expansion. It is used in 

 botany for the coverings of seeds. 



INTERCELLULAR SPACES. In 

 botany, the minute spaces existing 

 between the sides of cells. Along 

 these the movement of sap occurs in 

 herbs and the lower plants. In some 

 water plants they are large, to assist 

 natation. 



INTERFERENCE OF LIGHT. 

 The effects produced by causing two 

 pencils of light to be reflected or 

 transmitted at very minute intervals 

 or distances from each other, where- 

 by they interfere and produce col- 

 ours. If the light be homogeneous, 

 they produce bright and black bands. 



INTERVAL LANDS. Lands on 

 the margin of rivers. Alluvial lands. 



INTERNODE. The space be- 

 tween two knots, leaves, or leaf 

 buds, in stems. 



INTESTINALIA. Worms inhab- 

 iting the interior of the bodies of an- 

 imals. Entozoa. Those of the in- 

 testines are destroyed by purges and 

 large doses (2 oz.) of oil of turpentine. 



INTRADOS. The lower line or 

 curve of an arch. 



INTRORSE. Turned inward. 

 i INTUSSUSCEPTION. The fold- 

 ing of one portion of the intestines 

 into another. 



4:)3 



