On the Respiration of the Foetus^ etc. 225 



2. A thing will undergo condensation if its particles 

 which have expanded on being set in motion are 

 afterwards, on the subsidence of the motion, reduced to 

 narrower space. But neither in this way are the juices 

 of the Qgg condensed, inasmuch as they are colli- 

 quated and fermented by incubation, so that the motion 

 of their particles is necessarily greater than before. 



3. A thing might be condensed if some more subtle 

 matter interposed among its particles extricated itself, 

 so that the parts of the thing might approach nearer 

 to each other. And indeed it naturally occurs to one 

 to say that the rarer part of the albumen exhales, 

 and that the juice is reduced in consequence to less 

 bulk than before. But, indeed, this cannot happen in 

 the Qgg^ because its very compact shell and also the 

 membranes enveloping the juices of the egg^ prevent 

 any part of these juices escaping out of the &gg^ especi- 

 ally since in the incubated Qgg a greater space than 

 before is provided for the reception of these juices. 



4. Condensation of a thing may take place because 

 some elastic matter distributed among its particles 

 becomes afterwards less elastic ; and it is especially in 

 this way that the juices of the Qgg seem to be con- 

 densed. For it is probable that the air distributed 

 among the juices of the egg loses its elastic force on 

 account of the fermentation produced among these 

 juices by incubation, just as takes place in the mass of 

 the blood, as has been shown above. 



Since the seminal juices of the Qgg become more 

 contracted in this wa)^ by incubation and are reduced 

 to smaller bulk than before, there would be a vacuum 

 in the incubated egg if prudent nature had not, to 

 avoid this, stored in the egg a small quantity of air 

 which by its elastic force might extend itself into the 

 space left vacant by the condensation of the juices. 



P 



