1859-] LYELL'S CRITICISMS. g 



although if many of the other inhabitants were destroyed 

 [they] would cover the ground. We thus clearly see that, 

 their numbers are kept down, in almost every case, not by 

 climate, but by the struggle with other organisms. All this 

 you will perhaps think very obvious ; but, until I repeated it 

 to myself thousands of times, I took, as I believe, a wholly 

 v/rong view of the whole economy of nature. ... 



Hybridism. — I am so much pleased that you approve of 

 this chapter ; you would be astonished at the labor this cost 

 me ; so often was I, on what I believe was, the wrong scent.. 



Rudimentary Organs. — On the theory of Natural Selection 

 there is a wide distinction between Rudimentary Organs and 

 what you call germs of organs, and what I call in my bigger 

 book " nascent " organs. An organ should not be called 

 rudimentary unless it be useless — as teeth which never cut 

 through the gums — the papillae, representing the pistil in 

 male flowers, wing of Apteryx, or better, the little wings 

 under soldered elytra. These organs are now plainly useless, 

 and fl- fortiori^ they would be useless in a less developed 

 state. Natural Selection acts exclusively by preserving 

 successive slight, //j"^//// modifications. Hence Natural Selec- 

 tion cannot possibly make a useless or rudimentary organ. 

 Such organs are solely due to inheritance (as explained in 

 my discussion), and plainly bespeak an ancestor having the 

 organ in a useful condition. They may be, and often have 

 been, worked in for other purposes, and then they are only 

 rudimentary for the original function, which is sometimes 

 plainly apparent. A nascent organ, though little developed, 

 as it has to be developed must be useful in every stage of 

 development. As we cannot prophesy, we cannot tell what 

 organs are now nascent ; and nascent organs will rarely have 

 been handed down by certain members of a class from a re- 

 mote period to the present day, for beings with any im- 

 portant organ but little developed, will generally have 

 been supplanted by their descendants with the organ well 

 developed. The mammary glands in Ornithorhynchus may, 

 perhaps, be considered as nascent compared with the udders 



