COMMON OBJECTS WORTH EXAMINING. 305 



a small piece of the outer coating of the seed, place it 

 in a shallow cell with a thin cover above it. Arrange the 

 slide on the stage, focus the objective, and while look- 

 ing through the instrument allow a drop of water to 

 ,run into the cell and around the object. Immediately 

 the spiral vessels will seem to.be springing and grow- 

 ing out of the seed in a remarkable way. They are 

 held adherent by means of a mucilaginous substance, 

 soluble in water, and at a touch of the drop which dis- 

 solves their bonds they are set free, to the astonish- 

 ment of the observer who sees them for the first time. 

 19. Equisetum Spores (Equisdtum arve'nse) are 

 worth collecting and examining as transparent dry ob- 

 jects. The plant is Often called "Horse-tail" or 

 "Scouring-rush," and is to -to be found almost every- 

 where in sterile places, especially along the roadside 

 or the railroad. The spores are small, almost spherical, 

 and have four long narrow filaments which, when 

 moistened, curl and curve and twist, and toss the 

 spores about in every direction in what has been 

 styled a "quadrupedal hornpipe." If a quantity of 

 them .be placed on a slide and gently breathed upon, 

 the moisture of the breath will set those four long 

 threads into motion, and the dance will at once begin. 

 One of my friends makes a permanent mount of these, 

 peculiar spores by forming a cell of a single strand of 

 gold-lace fringe, and of course covering them with a 

 thin glass, fastened on with shellac cement, but so as 

 not to close the little apertures between the fibres of 

 the gold lace. By passing through these little 

 openings the moisture will at any time start the spores 

 on their "quadrupedal hornpipe," and when they are 

 dry the performance may be repeated. An ordinary 



