PROTOPLASM AND PLANT-CELLS. 



ferred. The most serviceable objectives are the -J and \ 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 somewliat 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); 3, 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. 3); stain some with 

 iodine, which will turn the protoplasm 

 brown or yellowisli 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. 



(J)) Make successive cross-sections of 

 tlie 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° Falir.) for a streaming motion 

 of the protoplasm in the liairs. 



-^,^ I"iQ. 2.— A little more than half 



rlace of a longitudinal section of the tip 



the specimen upon a block of ic^ and ^It^^-fbrefisS^eVody^m" 



note that the movement ceases. Warm root, that below it is the root-cap; 



rroin oto "■ *hiok outsr wall of the epider- 



again, etc. uiig. nx, young pith-cells; /.young 



(d) With similar specimens observe wood-cells; g, a young vessel; s,i, 



^, _ . !■/,%•]■ 1 ;„i, i,;ii„ inner younger part of root-cap; a, 



the effect of (1) loduie, winch kills (j^ outer older part of root-cap. 



and stains the protoplasm; (3) alcohol, 



Which kills and coagulates it; (8) glycerine, which withdraws water 



from it, and so collapses it. 



