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VII. 



THE PROBLEMS OF DISTRIBUTION AND 

 THEIR SOLUTION. 



PERSONS whose acquaintance with the methods of biological 

 study cannot be regarded as either extensive or profound, may 

 nevertheless regard themselves as perfectly capable of detailing 

 exactly and succinctly the four chief points involved in the considera- 

 tion of any living being. The history of an animal or plant, however 

 superficially that history may be viewed, presents a series of problems 

 which it is the business of the biologist to solve. These problems 

 resolve themselves sooner or later into four questions, the replies to 

 which, if given in full detail, supply us with a perfect knowledge of 

 the present and past life of the organism and its race. Query the 

 first, concerning the living being animal or plant, monad or man 

 resolves itself into the inquiry, ** What is it ? " To this question 

 the science of morphology, or that of structure, affords a reply. 

 The external form and the internal anatomy of the organism 

 are investigated under this primary question of the biologist. The 

 animal mechanism and the nature and relations of plant-tissues and 

 organs fall naturally within the scope of this question and its reply. 

 But the organism possesses its vital activities as well as its structural 

 details. In the essence of its nature, it presents for our study those 

 actions through which it maintains its own individual existence, and 

 that of its race or species likewise. 



A second question thus becomes imperative, and inquires, 

 " How does it live ? " To this query it is the province of phy- 

 siology, as the science of functions, to reply. Summarising the 

 life of any organism, three terms may be found to denote the 

 sum total of its vital activity. It firstly nourishes itself, and thus 

 engages in the exercise of the function of nutrition. It thuswise 

 provides for the maintenance of its individual frame. But as the 

 death of individuals thins out the ranks of the species, the exer- 

 cise of a second function, that of reproduction, provides for the 

 continuance of the race in time. Then, lastly, the animal or plant, 

 whatever its sphere or place in the organic series, or in the world at 

 large, exhibits certain relations to its surroundings. Deprived of 

 the means for exhibiting this relationship, the living being becomes 

 practically as the dead things around it. It is the power of relating 



K 



