PSYCHOLOGICAL AND ETHICAL ASPECTS. 



257 



■carelessness, which in one species finds expression in an organized 

 device. 



Conclusion. — The general character of the birds — the unsocial 

 life, the selfish cruelty of the nestlings, and the lazy parasitic habit — 

 have a common basis in the constitution. The insatiable appetite, the 

 small size of the reproductive organs, the smallness" of the eggs, the 

 sluggish parturition, the rapid growth of the young, the great prepon- 

 derance of males, the absence of true pairing, the degeneration of 

 maternal affection, are all correlated, and largely explicable, in terms 

 of the fundamental contrast between nutrition and reproduction, 

 between hunger and love. Similar unnatural or immoral instincts in 

 other birds, in mammals, and even in the lower animals, are explicable 

 in similar terms. The cuckoo's habit is a natural outcrop of the 

 general character or constitution, only one expression of a dominant 

 diathesis. 



In his recent important work on the" Origin of Species," Professor 

 Eimer maintains a similar view. He briefly criticises the Darwinian 

 explanation, which appears to him to postulate too many happy com- 

 binations. He maintains that the ancestral cuckoo acted deliberately in 

 the trick, and some of this deliberateness of device may still persist. 

 The explanation of the unnatural habit is to be found in the bird's 

 whole character and mode of life. In this connection Eimer empha- 

 sizes (a) the vagabond, restless habit; (6) the looseness of the sex- 

 relations, strong in passion, weak in love; (Y) the irregular and 

 gluttonous nutrition considered in relation to reproductive stimulus; 

 (cT) the slow laying of the eggs, itself dependent upon nutrition, and 

 pointing to physiological conditions which modify even the deeply- 

 rooted impulse and instinct to brood; (e) the degeneration of social 

 instincts, and the preponderance of the egoistic. 



VII. Egoism and Altruism. — The optimism which finds in 

 animal life only ' ' one hymn of love ' ' is inaccurate, like the pessimism 

 which sees throughout nothing but selfishness. Littre, Leconte, and 

 some others less definitely, have more reasonably recognized the coex- 

 istence of twin streams of egoism and altruism, which often merge for 

 a space without losing their distinctness, and are traceable to a com- 

 mon origin in the simplest forms of life. In the hunger and reproductive 

 attractions of the lowest organisms, the self-regarding and other- 

 regarding activities of the higher find their starting-point. Though 

 some vague consciousness is perhaps coexistent with life itself, we can 

 only speak with confidence of psychical egoism and altruism after a 

 central nervous system has been definitely established. At the same 

 time, the activities of even the lowest organisms are often distinctly 

 referable to either category. 



