EFFECTS OF HEAT UPON EGGS, 119 



sometimes find them quickened by this very exposure 

 into their larva or grub state.'* It would have been 

 well if some more accurate authority had been given for 

 so miraculous a fact than this general statement: the 

 appearance of maggots on broiled meat, from which the 

 inference is apparently made, seems rather to indicate 

 that eggs, or more probably ovo-viviparcus larvae, 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 egg 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 injuries with 

 more impunity than when very vivacious. We once 

 saw a very delicate young girl, emaciated with scro- 

 fula, 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 to 

 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, arid 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. f 



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

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



