1*28 
ON THE MIGRATION OF BIRDS. 
animals, as well as that of any other of their actions, will be clearly perceived. 
Indeed, without the aid of this science, the wisest metaphysician or most expe¬ 
rienced naturalist would alike fail in giving a probable solution. Three points 
respecting migration of birds deserve our attention: 1st, the propensity which 
prompts it; 2nd, the periodical excitement of the propensity; and 3rdly, the 
power which directs them in their flight. 
1. The Propensity. —Phrenology teaches us that there is an organ in Man 
which takes cognizance of the relative position of objects, remembers places, and 
gives the desire to travel . It is evidently this last impulse which is the cause of 
migration. Phrenologists have named the organ Locality, and if the faculty they 
have given to it be the correct one, we may reasonably expect to find it fully 
developed in migratory birds. This is actually the case, I have at present 
before me several crania of birds, and in the migratory species this organ is 
evidently larger than in those that stay with us throughout the year. Dr. 
Vimont, after the examination of several hundred skulls of quadrupeds and 
birds, states that, in all those that migrate, the organ of Locality is found “ form¬ 
ing a projection below the crest of the coronal bone, which joins the orbital 
angle/’* 
2. The Periodical Excitement of the Organ. —Dr. Bushnan states that the 
propensity to migration is excited only by a failure of food, and the change of 
temperature. As a proof of the correctness of his opinion, he mentions the 
following a curious fact , recorded some years ago? “ In the neighbourhood of the 
Carron Iron Works,” remarks the Doctor, <c where the temperature of the air, to 
a considerable extent around, must be very much above that natural to the 
climate, Swallows are said to remain the whole winter.”t If Dr. Bushnan 
could satisfactorily demonstrate the truth of this statement, his position would 
indeed be established. Until then he ought to remember that “ It is said” or 
“ They say ” although wonderful authorities in daily conversation, lose ail their 
importance when used with respect to matters of science. But the Doctor has 
yet another proof, which, he informs us, a puts the question beyond a doubt.” 
This is the experiment of Mr. Pearson, as detailed by Bewick4 On perusing 
the account, we find that Mr. Pearson, with considerable care and trouble, was 
able to keep several Swallows alive throughout winter. This is all. And this 
all , it is scarcely necessary to state, proves nothing in the present question. I 
think that after the repeated and uniform experience of naturalists, who have 
* Broussais’ Lectures on Phrenology. — Lancet (1835-6), Vol. I. p. 852. 
f The Philosophy of Reason and Instinct, by Dr. Bushnan, p. 171,—A work containing much 
interesting matter, but nothing to merit the title the Doctor has chosen to bestow upon it. It is 
very neatly reviewed in the Phrenological Journal for December, 1837, No. i., New Series. 
t Bewick’s Birds (Edit. 1832.), Vol. I., 300. 
