1913] The Ottawa Naturalist. 157 



important advantage, but probably there are many others yet 

 to be learned. But mark, that by acquiring adaptability, 

 Protoplasm lias secured the power to live under all sorts of 

 conditions, and this is no small advantage. 



Let us now turn to the ability of many plants to live in the 

 light. They must in some way prevent the actinic ravs. from 

 penetrating them through and through. We find that protoplasm 

 has responded to the danger of destruction by light, by the 

 extremely wise method of changing a deadly enemy into a friend 

 and even into a valuable servant. The change, however, is not 

 in the light, but in the protoplasm. In a part of its own substance 

 it develops a green coloring matter chlorophyll which it places 

 near the surface, and this absorbs the energy of the light, prevent- 

 ing its destroying the inner protoplasm, and also enabling it, 

 through the energy thus captured, to accomplish some most 

 astounding chemical changes. There are certain substances so 

 stable that when man in his chemical operations forms these 

 substances, lie lets them go as waste products. Among these are 

 prominently carbon dioxide and water. The energy required to 

 decompose these substances is so great that under no ordinary 

 conditions of manufacture can we undertake it . But protoplasm, 

 with the energy absorbed from sunlight, quietly takes apart 

 these refractory materials, and builds up their separated elements 

 into such complex substances as starch, fats, and proteids, and 

 as if in derision of man's efforts, gives these to man to be his 

 foods. Man, if properly informed, reverently accepts them, 

 confessing his ignorance and inability to make them for himself. 

 It is suggested in view of this power of green protoplasm, that 

 greenness is an important stage or condition of progress. Plants 

 lacking greenness have to live as man and the other animals do, 

 on the products of the energy and ability of the green plants. 

 It is because of tins power of green plants to manufacture an 

 abundance of food for themselves that large and enduring plant 

 structures and all kinds of animal life reccme possible. The 

 protoplasm of which we are made, develops in our surface layers 

 when exposed to light, a protective pigment, usually not green, 

 but brown or black. The presence of this permits of human life 

 in intensely lighted regions. Those who do not develop it readily, 

 retreat from the tropics or die. 



Having marked the victory of protoplasm over one enemy 

 we may proceed to see how it meets another. We have seen that 

 the presence of warmth and moisture are the prime conditions 

 essential to the life of protoplasm. It should now be noted that 

 these are incompatible conditions, inasmuch as warmth implies 

 the evaporation of moisture, and on the other hand the high 

 specific heat of water keeps at a comparatively low temperature 



