20 LIFE OF A TREE. 
highest interest; let us, therefore, glance at the 
first before speaking more in detail upon the 
second. 
Has the reader followed our recommendation, 
and watched the growth of the mustard-seed ? 
and has the question never arisen in his mind, 
how does this plant grow? how does it become 
larger and larger, and thus put out shoots which, 
respectively, seek the light, and bury themselves 
in the soil? Surely these questions deserve an 
answer, 1f one can be given. The question can 
be to some extent satisfactorily answered, for 
the microscope has shed its light upon the 
subject. By its means, then, we have ascer- 
tained the following facts; the merit of many of 
which is chiefiy due to the celebrated botanist 
Dr. Schleiden. 
By means of a very sharp razor we are able 
to cut off a thin morsel from the seed; and, on 
looking at this with a good microscope, we find 
it all made up of cells, looking like so much 
delicate and beautiful lace-work. Now, these 
little cells are every one of them little bladders, 
made of vegetable tissue for their sides, and 
containing inside a number of grains of starch 
