i BOTANY. 



That these movements are so generally overlooked is due 

 to the fact that in most cases they require the aid of a good 

 microscope, hut with such an instrument the student may 

 find evidences of motion in the protoplasm of every 

 plant. 



6. The imbibition of food, and the various movements, 

 are affected by the temperature of the protoplasm. They 

 take place best in temperatures ranging from that of an 

 ordinary living-room to that of a hot summer day (30° to 

 35° 0. = 68° to 95° Fahr.). A sudden change of tempera- 

 ture of even a few degrees will at once check or stop both 

 imbibition and movement ; even a sudden jarring will for 

 a time stop both kinds of activity. 



ProKtical Studies. — In the study of protoplasm it is necessary to 

 be provided with a compound microscope. For convenience of work- 

 ing, as well as for economy, the small instruments with short tube, 

 allowing easy use in a vertical position, are much to be preferred. 

 The most serviceable objectives are the i- and ^-inch, giving magnify- 

 ing powers of from about 100 to 500 diameters. Such a microscope 

 may be purchased in this country for from $35 to |30, and in Europe 

 for somewhat less. A very sharp scalpel or good razor is useful in 

 making sections. For the beginner but few reagents are necessary, 

 viz. : 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 (po- 

 tassic hydrate) ; 3, alcohol ; 4, several staining fluids, as haematox- 

 ylon, carmine, and safranin ; 5, glycerine. 



Note. — In the study of minute objects it is now the general cus- 

 tom to use metric measurements. The units used are the millimetre 

 and the micromillimetre, the former for the larger measurements, 

 the latter for the smaller. A millimetre equals .0394 of an inch, or 

 nearly one twenty-fifth of an inch. 



For the measurement of objects requiring high powers of the 

 microscope the micromillimetre is used. It is represented by the 

 Greek letter u, or by mmm. It is one thousandth of a millimetre, 

 and equals .0000394 of an inch, or nearly one twenty-five-thousandth 

 of an inch. A spore is thus said to measure 15 ft in diameter, 35 /i 

 In length, etc., or in the absence of the Greek letters we may record 



