THE ORIGIN OF THE HUMAN BODY 287 



functionless organs are atrophied or reduced. Facts, however, 

 prove the contrary ; for we find frequent instances of reduced 

 organs, which function, and, vice versa, of well-developed 

 organs which are functionless. The tail, for example, in cats, 

 dogs, and certain Catarrhine monkeys, though it discharges 

 neither the prehensile function that makes it useful in the 

 Platyrrhine monkey, nor the protective function that makes it 

 useful to horses and cattle in warding off flies, is, nevertheless, 

 despite its inutility or absence of function, a quite fully de- 

 veloped organ. Conversely, the reduced or undeveloped fin-like 

 wings of the penguin are by no means functionless, since they 

 enable this bird to swim through the water with great facility. 



To save his argument from this antagonism of the facts, 

 Darwin resorts to the ingenious expedient of distinguishing 

 between rudimentary organs and nascent organs. Rudimen- 

 tary organs are undeveloped organs, which are wholly, or 

 partially, useless. They have had a past, but have no future. 

 Nascent organs, on the contrary, are undeveloped organs, 

 which "are of high service to their possessors" ("Descent of 

 Man," ch. I, p. 28, 2nd ed.). They "are capable of further 

 development" (ibidem), and have, therefore, a future before 

 them. He gives the following examples of rudimentary 

 organs: "Rudimentary organs . . . are either quite useless, 

 such as teeth which never cut through the gums, or almost 

 useless, such as the wings of an ostrich, which serve merely 

 as sails." ("Origin of Species," 6th ed., ch. XIV, p. 469.) As 

 an example of a nascent organ, he gives the mammary glands 

 of the oviparous Duckbill: "The mammary glands of the 

 Ornithorhynchus may be considered, in comparison with the 

 udders of a cow, as in a nascent condition." (Op. cit., ch. XIV, 

 p. 470.) 



Darwin admits that it is hard to apply this distinction in 

 the concrete: "It is, however, often difficult to distinguish 

 between rudimentary and nascent organs; for we can judge 

 only by analogy whether a part is capable of further develop- 

 ment, in which case alone it deserves to be called nascent." 



