PROTOPLASM AND PLANT.CELLS. 3 
ferred. The most serviceable objectives are the $ and 4 inch, giving 
magnifying powers of from about 100 to 500 diameters. Such a 
microscope may be purchased in this country for from $30 to $40, 
and in Europe for somewhat less. A scalpel or good razor is useful 
in making sections. For the beginner the only reagents necessary 
are, 1, a solution of iodine (that made by first dissolving a very little 
potassic iodide in pure water and then adding iodine is the best for 
common use); 2, a solution of caustic potash in pure water (potassic 
hydrate); 3, alcohol; 4, some staining 
fluid, as magenta or carmine (common 
carmine ink is often quite satisfactory); 
5, glycerine. 
(a) Make very thin longitudinal sec- 
tions of the tips of the larger roots of 
Indian corn (Fig. 2); stain some with 
iodine, which will turn the protoplasm 
brown or yellowish brown; stain others 
with carmine; examine by the aid of 
the }inch objective. Make similar 
sections of the tip of a young shoot of 
the asparagus. 
(b) Make successive cross-sections of 
the root of Indian corn, beginning with 
the tip and receding five to ten centi- 
metres. Note the vacuoles and use 
iodine and carmine. Make similar sec- 
tions of young asparagus-stem. 
(c) Make a longitudinal section of 
the young part of a verbena-stem in 
such a manner as to leave on each 
margin a fringe of uninjured hairs. 
Mount carefully in pure water. Ex- 
amine at a high temperature (about 30° 
C. = 86° Fahr.) for a streaming motion 
_ 4 Fra. 2.—A little more than half 
of the protoplasm in the hairs. Place of a longitudinal section of the tip 
i i of a young root of the Indian Corn. 
the specimen upon a block of ice, and Sho part ehoves isthe boay-of Che 
note thatthe movement ceases. Warm root, that below it is the root-cap; 
‘ v, thick outer wall of the epider- 
again, ete. e mis; m, young pith-cells; f, young 
(@ With similar specimens observe wood-cells; g, a young vessel; s, 1, 
the effect of (1) iodine, which kills BRCLYOURES Dot rrooveap. 
and stains the protoplasm; (2) alcohol, 
which kills and coagulates it; (8) glycerine, which withdraws water 
from it, and so collapses it. 
