BULLETIN OF THE BUSSEY INSTITUTION. 333 
Mass. — of all places in the world — I came suddenly upon a soli- 
tary domestic pigeon feeding on the sandy ground at the edge of a 
clump of low bushes. On examining the place whence the bird 
flew, I found that the ‘‘ bushes” were stunted wild-cherry trees 
and that they were loaded with fruit. As there was not even a 
suggestion of any other kind of food in the neighborhood, there 
was no reason to doubt that the bird was really eating cherry- 
stones (or perhaps cherries) which had fallen from the trees or 
been dropped by other birds. 
The abundance of oat-husks in the dung found at the hay barn 
gives emphasis to the fact that oat-husks were seldom or never 
detected in the dung at the school, although the school birds had 
equal or perhaps better opportunity than the others to procure oats 
from horse-dung; and the great mass of this worthless material 
again suggests a doubt as to the general validity of the popular 
- opinion as to the high value of pigeon-dung as a fertilizer. There 
is always as a matter of course some uric acid in pigeon-dung, 
even in that which is most highly charged with inert matters; and 
since uric acid is known to be an extremely powerful manure, the 
dung must be valuable, chemically speaking, somewhat in propor- 
tion to the amount of this ingredient, — which is doubtless large in 
some cases, as when for example the diet of the birds is peas, or 
indeed almost any kind of huskless grain. But it is not unlikely 
that the special merit of the dung may depend not so much upon 
its chemical composition as upon the presence in it of some active 
‘‘ ferment,” or upon some special fitness which the dung may have 
for harboring the ferement. ‘The idea is suggested by the tradi- 
tional use of pigeon-dung as a ferment by the morocco-dressers ; and 
it is borne out in some part by the fact that pigeon-dung was for- 
merly highly esteemed in the preparation of nitre-beds also. In- 
deed, Pietsch * is said to have written, in 1749, that for salpetre- 
making pigeon-dung does better than any other kind of excrement. 
The cherry-stones eaten by the barn-pigeons were manifestly of 
the wild species for the most part, as was not unnatural in view of 
the greater distance of the locality from gardens and fruit-farms 
as compared with the school-building. In harmony with the com- 
parative thinness and tenderness of the shells of the wild-cherry 
stones the fragments found at the barn were in general smaller 
* Cited by the authors of the ‘‘ Recueil des Mémoires sur la Formation du 
Salpétre,” in ‘‘ Mémoires des Savans Etrangérs,” 1786, 11. 24. 
