( 



479 



OBSERVATIONS concerning 



germ 



weather, had his wheat all eaten out ; the flies were 

 crawling out of the ears, and this whilft the wheat was 



ftanding. 



Again, that the convidion may be as full as poflible, 



it is an indifputable certainty, that this maggot eats from 

 the upper end of the grain, as it ftands in its hulk, dowa 

 to the lower end, and comes out in a fly a little above th^ 



Now to fuppofe that thefe eggs are laid conftantly 

 upon that end of the grain, is to believe this fly capable 

 of diftinguifhing fuch particular end, in every confufed 



diredion that the grain may be thrown into after it is 

 thrafhed out; and therefore the notion of the fly's laying 

 its egg upon the outfideof the grain, and that egg's never 

 being dlflodged, and the maggot's hatching upon that end, 

 and eating into the grain, without being removed from 

 that particular end, mufl be an abfurdity of the firft mag- 

 nitude. In the hulk indeed the fly might find that certain 

 end of the grain, bccaufe in that it always lies in its pro- 

 per diredion, and it is reafonable to conclude that inftind 

 would ferve a fly for fuch a purpofe ; but then this cannot 

 remove the abfurdity before taken notice of, that of laying 

 its egg upon that end of the grain confl:antly, as well be- 

 fore as after it is thraflied. 



Nature, I may fay, from the minutenefs of her ways 



in efFeding her intended purpofes, is frequently out of 



the comprehenfion of man, and although his microfcopical 

 improvements upon vifion have helped him to many dlf 

 coveries, numerous are the things that feem ftill to remain 

 as a fecret to him. V/e can fee in fome flies their imme- 

 diate changes from the firft proccfs of propagation, qiaite 

 through their periods of life; and from thence we are in- 

 clined to pronounce a rational hiftory of their continuance, 

 brood after brood : Yet in fome flies, though we can carry 

 them through all thefe feveral changes, there are certain 

 pha^nomcna not to be accounted for; particularly, how 

 the length of time between their changes into flies, and 

 their laying their eggs for the continuance of their fpccies, 



is 



r- r 



£A^ 



»ltHt 



