.62 CHAPTERS ON EVOLUTION. 



The investigation of life from any point of view leads us to seek 

 in the lower confines of the living worlds, the subjects which are most 

 likely to present us with the simplest and most elementary manifesta- 

 tions of living force. The life-history of- the higher animal and 

 plant appears before us as the acme of intricate operations, and as a 

 complex collection of manufactories and organisations, the working of 

 which may well puzzle and perplex us even in its plainest details. 

 The mere study of a single function in the higher organism is beset 

 with difficulties of greater or less kind. The circulation of the blood, 

 the elaboration of sap not to speak of the problems involved in con- 

 sidering animal and plant sensibility and the functions of nerves are 

 illustrations of points in the history of the high animal or plant which 

 involve problems of well-nigh inexplicable nature in their study. 

 Hence the prevailing tendency in research of the kind before us has 

 been indicated by the selection of the lowest fields of life as the 

 ground best adapted to yield promising results to the scientific 

 inquirer. The lower animal or plant, as we shall presently see, 

 makes its appearance before us as a body apparently of extremely 

 simple structure and nature. Presenting us at the most with the appear- 

 ance of a single "cell " (Fig. 19), the lower organism might be thought 

 to yield to scientific scrutiny some clear knowledge of the nature of 

 the powers which rule its destinies. And such a supposition might 

 likewise be presumed to gather strength in the hopefulness of the 

 idea that, as the higher animal or plant is but an aggregation of 

 units, each representing the single " cell " of lower life, the study of 

 the low organism should reveal to us, as by deputy, the secrets of the 

 higher organisation. But the problem is hardly resolvable into con- 

 ditions such as have just been indicated. The living being in higher 

 life is not a mere collection of units, the disposition of which can be 

 mathematically calculated and mechanically analysed. The condi- 

 tions which might well enough bound the discovery of the mechanfcal 

 contrivances of mankind, are not those which environ the puzzle of 

 life. The problem which faces us as we gaze at the complex 

 organism with its multifarious functions, is just as recondite as when, 

 by aid of the microscope, we can look through and through the speck 

 of protoplasm which seems hardly to warrant the term " animalcule " 

 bestowed upon it. Thus the mere environments of the problem 

 of living and being, constitute a difficulty of no ordinary kind, and 

 hedge the nature of the life which is in the animal or plant with a 

 mystery that appears to loom darkly enough, even before the shining 

 lights of these latter days. 



Although the solution of the problem concerning the nature of 

 life may be said in some respects, therefore, to have gained but little 

 aid from researches into the lower worlds of life that people the 

 stagnant drop beings which find a home in dimensions that 



