_ 
BULLETIN OF THE BUSSEY INSTITUTION. 267 
that was consumed ; and it appeared that beside their 34 grammes 
of oats, the three mice ate daily, during three consecutive days, 
12 balls of putty of the size above mentioned, weighing all told 
20 grammes, and containing 16.7 grms. of whiting and 3.3 grms. 
of oil. That is to say, each of the mice swallowed every day and 
discharged again as dung more than 54 grms. of dry whiting. But 
since these particular mice weighed little more than fifteen grammes 
apiece, it appears that the quantity of inert earth (whiting) that 
passed through them daily amounted to more than one third the 
weight of the animals. ‘It is as if more than 50 Ibs. of dry chalk 
were to pass daily through a man of 150 lbs. weight. 
It should be said that I made no attempt to determine how long 
this large consumption of whiting could be kept up. Ten or twelve 
balls of putty a day appeared to be very nearly the limit of the 
amount which the three mice were willing to consume, but it seemed 
probable that this limited rate of consumption could be maintained 
for a long time, if not for an indefinite period. Several attempts 
were made in January to induce the mice to eat fifteen balls in- 
stead of twelve, but they invariably left one or two of the balls 
uneaten in this case. 
The foregoing results afford a striking illustration of the power 
of the animals to extract very small amounts of nutritive matters 
from a great mass of inert material. For the sake of the 34 grms. 
of oil, with which it was admixed, the mice swallowed more than 
five times this amount of whiting.* 
* A somewhat analogous instance is that of the bones eaten by dogs and 
other carniverous animals. About one third part of the bone may be regarded 
as organic matter (ossein), but from the immobility of the ossein and its in- 
accessible position, enclosed as it is by the bone-earth, it seems improbable 
that anything like the whole of that contained in the bones is digested. 
In some wild ‘districts, sheep and cattle are accustomed to eat very con- . 
siderable quantities of certain clayey and sandy earths for the sake of a very 
small proportion of common salt which these earths contain, and it has been 
noticed that the animals appear none the worse for this habit of dirt-eating. 
Compare Muir, in ‘‘ Chemical News” 36. 202, and Liebig, in his ‘‘ Familiar 
Letters on Chemistry,” London, 1851, p. 414, note, — citing the Mogling’sche 
** Annalen,” 1847, 2. ‘29, 
So, too, William Bartram (in his ‘‘ Travels through North and South Caro- 
lina, Georgia, Florida, &c.,’”’ London, 1792, page 39), describing a Buffalo 
Lick some 80 miles from Augusta, Georgia, on the ridge which separates the 
waters of the Savannah River from those of the Altamaha, says: ‘‘ The place 
called the lick is nearly level and contains three or four acres. The earth, 
from the superficies to an unknown depth, is an almost white or cinerous- 
