OBSERVATIONS ON THE CUCKOO. 71 
berance of its stomach, which, they hastily conclude, 
must render the act of incubation difficult, if not 
impracticable ; but when we consider that several 
birds, as the Owl, Goatsucker, &c., whose stomachs 
are in those respects similar to that of the Cuckoo, do 
incubate their own eggs, the insufficiency of this 
imaginary cause will be very apparent. 
Buffon supposes that female Cuckoos lay their 
eggs in the nests of other birds to prevent the males, 
which he states occasionally prey upon eggs, from 
destroying them*. The chief objection to this sup- 
position arises from the deficiency of evidence in sup- 
port of this charge brought against the males. 
According to the ‘ Physiognomical System’ of Drs. 
Gall and Spurzheim, Cuckoos transfer the care of 
their progeny to strangers in consequence of the 
imperfect development of certain cerebral organs, 
termed by those authors organs of constructiveness 
and philoprogenitiveness, whose functions are thus 
necessarily circumscribed. I shall not here discuss 
the merits of this system, which, notwithstanding the 
ridicule that is bestowed upon it, is at least entitled 
to a patient and candid investigation, but shall pro- 
ceed to consider the reason assigned by Dr. Jenner 
for the singularities of the Cuckoo. This gentleman 
conjectures, as I have already stated, that the short 
stay which Cuckoos make in this country is the true 
reason why they do not bring up their own young, as 
* « Histoire Naturelle des Oiseaux,’ tome sixiéme. 
