434 ON GENERATION. 



tinually carried upwards and downwards by a natural move- 

 ment, and are excited by any irritation to coughing and more 

 frequent action ; but they cannot form and regulate the voice, 

 nor can singing be executed, without the assistance, and in 

 some sort the command, of the sensorium commune. 



But these matters will be more fully handled when we come 

 to speak of the actions and uses of the brain, and to consider 

 the vital principle or soul. So much we have thought fit to 

 say by the way, that we might show the respect in which we 

 hold our illustrious teachers, and our anxiety to carry them 

 along with us in our labours. 



EXERCISE THE FIFTY-EIGHTH. 



Of the nutrition of the chick in ovo. 



That the authority of the ancients is not to be rashly thrown 

 off appears in this : it was formerly current doctrine, though 

 many at the present day, Fabricius 1 among the number, reject 

 it as a delusion and a foolish idea, that the embryo sucked in 

 its mother's womb. This idea nevertheless had Democritus, 

 Epicurus, and Hippocrates for its supporters ; and the father 

 of physic contends for it on two principal grounds : " Unless 

 the foetus sucked/' he says, 2 "how should excrements be 

 formed ? or how should it know how to suck immediately after 

 it is born ?" 



Now, whilst in other instances it is customary to swear by 

 the bare statement of this ancient and most distinguished 

 writer, his ipse dixit (O.VTOQ 6^*7) sufficing, because he here 

 makes an assertion contrary to the commonly received 

 opinion, Fabricius not only denies the statement, but spurns 

 the arguments in support of his conclusion. We, however, 

 leave it to the judgment of skilful anatomists and learned 

 physicians to say whether our observations on the generation of 

 animals do not proclaim this opinion of Hippocrates to be not 

 merely probable, but even necessary. 



All admit that the foetus in utero swims in the midst of an 

 1 De Form. Foetu, pp. 19 et 134. 2 Lib. de Carn. et de Nat. Pueri. 



