SOME PROTECTIVE DEVICES AMONG PLANTS. 



THE study of natural objects has the great advantage of exciting 

 not contempt, but rather the highest respect, and even a rever- 

 ential awe. This is particularly true of that fascinating but un- 

 fathomed mystery, protoplasm. Chemistry speaks with considerable 

 assurance in relation to the mineral kingdom, but its highly perfected 

 processes and instruments are unable to distinguish the protoplasm 

 of a statesman's brain from that of a tadpole's brain, or from that 

 which produces the bark of a tree. The entire living world in its 

 innumerable forms is but the varied expression of protoplasm. In 

 connection with this kind of matter alone is life known. The 

 variety is the response of an irritable substance to the conditions and 

 forces acting on it. 



In the vegetable kingdom organization is far from reaching the 

 perfection shown in animals. Each branch of a tree is in many re- 

 spects the rival of every other branch, and is likely to benefit by the 

 destruction of the other branches. The same is true to a less extent 

 among the cells of any one set of organs. Evidently, however, the 

 cells of the roots cannot rival those of the leaves, because of differing 

 functions. Here we see the effect of organization, which in animals 

 has reached such a stage as to practically prevent the duplication of 

 parts having exactly the same function. There is in the animal body 

 such an absence of rivalry as to make an injury to any member the 

 cause of lack of efficiency to the whole body. The limitation in the 

 size of present day animals is probably due to the necessity for the 

 avoidance of duplicate and therefore rivalling parts. We may pos- 

 sibly attribute the remarkable success of insect life to such perfection 

 of organization that even the two processes of growth and develop- 

 ment have become in many orders quite distinct from each other, and 

 occupy different stages in the life history. In plants and in other 

 classes of animals these processes are rivals for the life energy re- 

 quired for their completion. 



Sufficient has been said to indicate that we may expect more or 

 less effective adaptations where this sensitive material, protoplasm, 

 meets conditions which threaten its very existence. Such a condition 

 is lack of water in connection with plant life, and to this one factor 

 of environment we shall confine our attention in this article. 



By drying plants and parts of plants at a temperature just above 

 the boiling point of water, we can readily prove that all parts of 



