THE EVIDENCE FROM DEGENERATION. 349 



might remain for ages in their present lowly condition. And geology 

 tells us that some of the lowest forms, as the foraminifera (Fig. 248), 

 infusoria, and rhizopods, have remained for an enormous period in 

 nearly their present state. But," adds Darwin, with a characteristically 

 impartial view of matters, "to suppose that most of the many now 

 existing low forms have not in the least advanced since the first dawn 

 of life would be extremely rash ; for every naturalist who has dissected 

 some of the beings now ranked as very low in the scale must have 

 been struck with their really wondrous and beautiful organisation." 



Thus one of the plainest facts of natural history, namely, that in 

 even one group or class of animals we find forms of exceedingly low 

 structure included along with animals of high organisation the 

 apparently diverse bodies being really modelled on the one and the 

 same type is explained by the consideration that with different con- 

 ditions, or with varied conditions acting differently upon unlike 

 constitutions, we expect to find extreme differences in the rank to 

 which the members of a class may attain. In the class of fishes we 

 find the worm-like clear-bodied lancelet of an inch long, associated 

 with the ferocious shark, the active dogfish, or the agile food-fishes of 

 our table. But, as Darwin remarks, the shark would not tend to sup- 

 plant the lancelet, their spheres and their conditions of existence 

 being of diverse nature. The same remark applies to many other 

 classes of living beings. So that lowly beings still live as such 

 amongst us, and preserve the primitive simplicity of their race, firstly, 

 because the conditions of life and their limited numbers may not 

 have induced any great competition or struggle for existence. On 

 the "let well alone" principle, we may understand why some 

 animals, such as the lancelet itself, have lagged behind in the race 

 after progress. Then, secondly, as Darwin remarks, favourable 

 variations, by way of beginning the work of progress, may never 

 have appeared a result due, probably, as much to hidden causes 

 within the living being as to outside conditions. We may not fail 

 to note, lastly, that the simpler and more uniform these latter 

 conditions are as represented in the abysses of the ocean, for 

 example the less incentive is there for the progress and evolution 

 of the races which dwell in their midst. 



This somewhat lengthy introduction to the subject of degeneration 

 and its results, is in its way necessary for the full appreciation of the 

 fashion in which degeneration relates itself to the other conditions of 

 life. From the preceding reflections it becomes clear that three 

 possibilities of life await each living being. Either it remains primi- 

 tive and unchanged, or it progresses towards a higher type, or, last 

 of all, it backslides and retrogresses. The first condition, that of 

 stability, is, as already noted, perfectly consistent with the doctrine of 

 descent; and the two latter conditions also form part and parcel of that 



