

186 REPoRT OF THE First AssIsTANT OF THE 
\ 
calcium equal to 7.62 grammes carbonate of line. The oyster shells 
taken by them contained 93.80 grammes carbonate of lime. 
During the second period the hens laid twenty-one eggs, which 
were produced at the rate of one pound for every 2.59 lbs. of water- 
free food. These eggs contained calcium equal to 87.88 grammes 
carbonate of lime, the shells alone containing 86.6 grammes. The 
food consumed and drinking water given them contained calcium 
equal to 10.08 grammes carbonate of lime. The oyster shells taken 
by them contained 180.99 grammes corbonate of lime. Of the 
carbonate of lime contained in the eggs during the first period 40.81 
grammes, over eighty-four per cent, and of that in the eggs during 
the second period 77.80 grammes, over eighty-six per cent, is unac- 
counted for except by the carbonate of lime in the oyster shells, of 
which 99.2 grammes were consumed during the first period and 191.4 
grammes during the second. . 
The difference is so great that no other conclusion seems possible * 
than that the egg shells were constructed from material supplied in 
large part by the oyster shells. 
These hens lost in weight a total of five ounces during the first 
period and a total of two ounces during the second, a change in 
weight of little consequence and one that might have occurred at any 
time within a few hours. 
At the same time with these feeding trials another lot of three hens — 
was fed under exactly similar conditions except that coarsely pounded — 
glass was given the hens instead of oyster shells. No dark colored 
or opaque glass was used, broken bottles, carboys and window glass 
furnishing the supply. An average sample of the glass contained 
5.44 per cent of calcium, no trace of which, however, was soluble in 
nitric or hydrochloric acid or aqua regia. 
These hens did not lay as well as those having oyster shells, and 
two became sick (feverish and unable to stand). They recovered in 
about two days, however, after a little alcohol and oil was given them 
and the glass removed from the pen. Although pounded glass has 
been given to hens and chicks here for two years this is the only time 
that any symptoms of disease have been observed to accompany its 
use. The trouble was probably due to the excessive amount of glass 
swallowed, for while the oyster shells eaten by the hens formed 4.5 
and 7.1 per cent of the total water-free material, the glass formed 31.3 
per cent of the total water-free material eaten by the hens in the first — 
period, and in the second when the hens were allowed less than they 
wanted, 26.1 per cent. Orin the one period the hens consumed an 
amount of glass weighing 45.8 per cent a3 much as all the dry matter of 

