_fe_ are derived _feles_, "cat" (the fruitful animal); _fe-num_, "hay"; _fe-cundus_, "fertile"; _fe-lix,_ "happy" (fruitful). The corresponding verb in Greek is [Greek: _phuein_], "to grow, to spring forth, to come into being," whence the following: [Greek: _phusis_], "a creature, birth, nature,"--nature is "all that has had birth"; [Greek: _phuton_] "something grown, plant, tree, creature, child"; [Greek: _phulae, philon_] "race, clan, tribe,"--the "aggregate of those born in a certain way or place"; [Greek: _phus_], "son"; [Greek: _phusas_], "father," etc. In English, we formerly had the phrase "to look _babies_ in the eyes," and we still speak of the _pupil_ of the eye, the old folk-belief having been able to assert itself in the every-day speech of the race,--the thought that the soul looked out of the windows of the eyes. In Latin, _pupilla pupila,_ "girl, pupil of the eye," is a diminutive of _pupa_ (_puppa_), "girl, damsel, doll, puppet"; other related words are _pupulus_, "little boy"; _pupillus_, "orphan, ward," our _pupil_; _pupulus_, "little child, boy"; _pupus_, "child, boy." The radical of all these is _pu_, "to beget"; whence are derived also the following: _puer_, "child, boy"; _puella_ (for _puerula_), a diminutive of _puer_, "girl"; _pusus_, "boy"; _pusio_, "little boy," _pusillus_; "a very little boy"; _putus_, "boy"; _putillus_, "little boy"; _putilla_, "little girl,"--here belongs also _pusillanimus_, "small-minded, boy-minded"; _pubis_, "ripe, adult"; _pubertas_, "puberty, maturity"; _pullus_, "a young animal, a fowl," whence our _pullet_. In Greek we find the cognate words [Greek: polos] "a young animal," related to our _foal, filly_; [Greek: polion], "pony," and, as some, perhaps too venturesome, have suggested, [Greek: pais], "child," with its numerous derivatives in the scientifical nomenclature and phraseology of to-day. In Sanskrit we have _putra_, "son," a word familiar as a suffix in river-names,--_Brahmaputra_, "son of Brahma,"--_pota_, "the young of an animal," etc. Skeat thinks that our word _boy_, borrowed from Low German and probably related to the Modern High German _Bube_, whence the familiar "bub" of American colloquial speech, is cognate with Latin _pupus_. To this stock of words our _babe_, with its diminutive _baby_, seems not akin. Skeat, rejecting the theory that it is a reduplicative child-word, like _papa_, sees in it merely a modification (infantine, perhaps) of the Celtic _maban_, diminutive of _mab_, "son," and hence related to _maid_, the particular etymology of which is discussed elsewhere.