IN RELATION TO THE DISTRIBUTION OF SPECIES. 
29 
from one river to another without loss of vitality by an Otter or Heron or other 
aquatic bird, if lodged in the mouth of the one — with the proviso mentioned above, 
— or in the bill of the other ; or during a time of frost or snow if adhering to the 
feet of either of the animals mentioned? 
When my attention was first given to the subject, which was before I was favoured 
with your letter, I imagined that the impregnated ova might be conveyed in the 
stomach of birds, taken up from one river, and, it might be, disgorged in another, 
without loss of vitality, inasmuch as the ova of the Salmon found in the stomach of 
a trout have been known to be productive when returned to water. For an authen- 
ticated instance of the kind, I may refer to a report by Mr. Halliday, the agent of 
Messrs. Edmund and Thomas Ashworth, on the artificial process of breeding Salmon 
carried on at Oughterard in Galway*. It was to test this conjecture that the experi- 
ments in the fourth section were made; and, I may add, with negative results, know- 
ing as we do, that the temperature of the stomach of birds is usually above 100° of 
Fahr. 
Besides the main and express object for which the preceding experiments were 
made, I trust the results may be of some use in aiding to solve the question as to the 
period, the age, at which the impregnated ova of fish are most retentive of life, and 
consequently, are in the state best fitted for transport without loss of life ; and that 
those in the two last sections may help to explain the absence of the Salmonidae in 
tropical seas and in those approaching to them in temperature, such as the Mediter- 
ranean ; and may also throw a little light on some of the peculiar habits as well as 
on the localities of their migratory species. 
I am, my dear Sir, yours very truly, 
Lesketh How, Amhleside, John Davy. 
March 21, 1855. 
* The Report is attached to “ A Treatise on the Propagation of Salmon and other Fish,” by Edmund and 
Thomas Ashworth: London, Simpkin and Marshall, 1853 . 
