IQ2 STRUCTURE AND LIFE HISTORIES 
which arise from the study of so lowly an organism as a 
fern. Some of these have been partially solved prob- 
ably none of them has been completely solved. In fact, 
we may say that our ignorance of life-processes greatly ex- 
ceeds our knowledge. Very much more remains to be 
ascertained than has already been found out; for example, 
what is protoplasm? Nobody really knows. We have 
analyzed the substance chemically, we have carefully 
examined and tried (but without complete success) to 
describe its structure. We know it is more than merely 
a chemical compound. It is a historical substance. A 
watch, as such, is not. The metal and parts of which a 
watch is made, have, it is true, a past history; but the 
watch comes from the hands of its maker de novo, without 
any past history as a watch. But not so the plant cell. 
It has an ancestry as a cell; its protoplasm has what we 
may call a physiological memory of the past. It is what 
it is, not merely because of its present condition, but 
because its ancestral cells have had certain experiences. 
We can never understand a plant protoplast merely by 
studying it; we must know something of its genealogy and 
its past history. 
What is the origin of the sporophyte, and how did 
there come to be two alternating generations? What is 
the meaning of fertilization; what the mechanism and 
laws of inheritance? How did there come to be on the 
earth such plants as ferns? What was the origin of life? 
What is life? No one can give complete answers to these 
questions; but the purpose of the study of botany is to 
help fit us to seek the answers intelligently. To those 
who are interested in problems of this sort, nothing can 
be more fascinating, nor more profitable. 
