Mifcellanea Curlofa. 199 



tents are compreft ; to which the fermentative 

 motion naturally refifts. But both Bodies be* 

 ing as well compreffible • as dilatable, and both 

 having an expanfive motion impreft upon them 

 by Incubation, the Compreffion and Renkency 

 will be mutual* but varied in degree, accord- 

 ing as either, through the variation of Circuoi- 

 ftances, {hall prevail. By this means, an Al- 

 ternation of Compreffion and Dilatation will be 

 produc'd in both, anfwering the nfpimtory mo- 

 tion, by which a motion will be communica- 

 ted, which, as fbon as the Organs by which 

 it mould be regulated are compleated, will in 

 the Body of the Pullus be regular and circula- 

 tory. 



Fabritius ab Aquapendente, and after him, our 

 Great Dr, Harvey, have afiign'd divers Ufies to 

 this Cavity or Air Veficle, the Extravagance of 

 which have perhaps deterr'd others from en qui* 

 ring fo much into the life, as the Importance 

 of it requir'd. But though I can't agree to that 

 Perforation, Refrigeration, and Refpiration^ which 

 they make it the Inftrument of ; yet perhaps 

 the Air, that was inclos'd in that Cavity, may 

 through the Augmentation of the Body of the 

 Pullus, and its own Rarefaction (which is at laft 

 fo great as to occupy half the Shell) break 

 the Membrane, which feparated it from the Pa/* 

 lus, and thereby give fo much Refpiration as to 

 form the chirping Voice, which is ofren heard 

 before the breaking of the Shell, and with it 

 give an addition of Strength to enable ic to break 

 the Shell. But how it mould refpire fooner, is 

 to me inconceivable. 



There 



