216 NATURAL HISTORY 



spiration. 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 spar- 

 rows, &c. can be induced at all to sit on the egg of the 

 cuckoo without being scandalized at the vast dispropor- 

 tioned size of the supposititious egg: but the brute 

 creation, I suppose, have very little idea of size, colour, 

 or number. For the common hen, I know, when the 

 fury of incubation is on her, will sit on a single shape- 

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

 withdrawn ; and, moreover, a hen-turkey, in the same 

 circumstances, 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 endeavour to get a hen, and to examine 1 . 



1 In a female cuckoo, dissected at the breeding season, I found only 

 one ovum in the oviduct, situated in the calcifying segment, or uterus as 

 it is termed, and with the shell partially formed : the rest of the oviduct 

 was disposed in close transverse folds, and not exceeding two lines in 

 diameter. The ovary, besides a cluster of small ova, contained one ovum 

 about half an inch in diameter, and no doubt ready to pass into the ovi- 

 duct, when disburthened of the egg which it was then perfecting. The 

 ovum or yelk, next in size, was about three lines in diameter, but whe- 

 ther its further development would have been progressive or retrograde 

 can only be conjectured. As only one empty and collapsed calyx existed 

 in the ovary, the egg in the oviduct must have been the first which the 

 cuckoo would have laid this year. The appearances generally bespoke 

 a bird that produced more than one egg in the season ; but whether one, 

 two, or more additional ova would have passed into the oviduct I am 

 unable to determine. 



I am not aware that more than one ovum is ever contained in the ovi- 

 duct at one time in any bird. R. O. 



