FULLER QUOTATIONS FROM < ZOONOMIA? 221 



when combined, produce nitrous acid, which now ac- 

 quires the property of dissolving silver; so that with 

 every new additional part to the embryon, as of the 

 throat or lungs, I suppose a new animal appetency to 

 be produced." * 



#**** 

 Here, again, it should be insisted on that neither 

 can the "additional part" precede "the appetency," 

 nor the appetency precede the additional part for long 

 together the two advance nearly pari passu; sometimes 

 the power a little ahead of the desire, stimulates the 

 desire to an activity it would not otherwise have known ; 

 as those who have more money than they once had, feel 

 new wants which they would not have known if they 

 had not obtained the power to gratify them; some- 

 times, on the other hand, the desire is a little more 

 active than the power, and pulls the power up to itself 

 by means of the effort made to gratify the desire as 

 those who want a little more of this or that than they 

 have money to pay for, will try all manner of shifts to 

 earn the additional money they want, unless it is so 

 much in excess of their present means that they give 

 up the endeavour as hopeless; but whichever gets 

 ahead, immediately sets to work to pull the other level 

 with it, the getting ahead either of power or desire 

 being exclusively the work of external agencies, while 

 the coming up level of the other is due to agencies 

 that are incorporate with the organism itself. Thus an 

 unusually abundant supply of food, due to causes 

 entirely beyond the control of the individual, is an 

 * ' Zoonomia,' vol. i. p. 503. 



