EFFECTS OF HEAT UPON EGGS. 119 



sometimes find them quickened by this very exposure 

 into their larva or grub state*." It woiild have been 

 well if some more accurate authority liad been given for 

 so miraculous a fact than this general statement ; the 

 appearance of mag-g-ots on broiled meat, from which the 

 inference is apparently made, seems rather to indicate 

 that eggs, or more probably ovo-viviparous larvse, had 

 been deposited there, not before^ but after the broiling. 



One certain result of all such experiments is, that 

 eggs are more capable of withstanding heat than the 

 animals producing them; and from similar experi- 

 ments the same law appears to hold with the seeds 

 of plants, which also withstand more heat than 

 eggs. Water increases the destructive influence of 

 heat. The causes upon which these curious facts 

 depend do not appear to be well understood. It is 

 certain, however, that the life of an animal in the G^<y 

 is feeble, or at least lethargic, in comparison with that 

 of the animal produced ; and that animals, when in a 

 state of very feeble animation, resist external inju- 

 ries with more impunity than when very vivacious. 

 We once saw a very delicate young girl, emaciated 

 with scrofula, have her leg amputated without even 

 heaving a sigh; while a robust Irish labourer, who 

 underwent the same operation immediately after her, 

 roared like a bull. 



Experiments prove that the fluids of eggs, and con- 

 sequently of their germs, are more abundant than in 

 vegetable seeds; and this excess of fluid may tend (o 

 destroy the germ more readily, from heat expanding 

 the fluids, and thus putting them in motion : for then 

 they must strike violently against the tender parts of the 

 germs, and rupture and destroy them. Hence seeds 

 exposed to heat are killed at lower degrees in water, 

 than if dry, in the same way as ice will melt sooner 

 in warm water than in air of equal temperature i". 



* Good's Book of Nature, vol. i. p. 221 ; 1st edit, 

 t Spallanzani, Tracts by Dalyell, vol. i, p. 43 



