NATURAL HISTORY OF SELBORNE 107 



reason. The thriving at those times appears to me to arise 

 altogether from the gentle check which the cold throws upon 

 insensible perspiration. The case is just the same with black- 

 birds, etc. ; and farmers and warreners observe, the first, 

 that their hogs fat more kindly at such times, and the latter 

 that their rabbits are never in such good case as in a gentle 

 frost. But when frosts are severe, and of long continuance, 

 the case is soon altered ; for then a want of food soon over- 

 balances the repletion occasioned by a checked perspiration. 

 I have observed, moreover, that some human constitutions are 

 more inclined to plumpness in winter than in summer. 



When birds come to suffer by severe frost, I find that the 

 first that fail and die are the redwing-fieldfares, and then the 

 song-thrushes. 



You wonder, with good reason, that the hedge-sparrows, etc., 

 can be induced at all to sit on the egg of the cuckoo without 

 being scandalized at the vast disproportionate size of the sup- 

 posititious egg ; but the brute creation, I suppose, have very 

 little idea of size, color, or number. For the common hen, I 

 know, when the fury of incubation is on her, will sit on a single 

 shapeless stone instead of a nest full of eggs that have been 

 withdrawn : and, moreover, a hen turkey, in the same circum- 

 stances, would sit on in the empty nest till she perished with 

 hunger. 



I think the matter might easily be determined whether a 

 cuckoo lays one or two eggs, or more, in a season, by opening 

 a female during the laying time. If more than one was come 

 down out of the ovary and advanced to a good size, doubtless 

 then she would that spring lay more than one. 



I will endeavor to get a hen, and to examine. 



Your supposition that there may be some natural obstruc- 

 tion in singing birds while they are mute, and that when this 

 is removed the song recommences, is new and bold : I wish 

 you could discover some good grounds for this suspicion. 



I was glad you were pleased with my specimen of the capri- 

 mulgus, or fern-owl ; you were, I find, acquainted with the bird 

 before. 



When we meet I shall be glad to have some conversation 

 with you concerning the proposal you make of my drawing 



