266 BULLETIN OF THE BUSSEY INSTITUTION. 
putty should be eaten by mice an opening would be made beyond 
the trap for the free passage of sewer gas into the house. On pro- 
ceeding to make enquiries of plumbers as to whether they had ever 
noticed the occurrence of this event, I found that they are familiar 
with it. One master-workman assured me that in fitting up the 
water-closets of new houses the mice had sometimes destroyed the 
putty-joints of his work at the top or bottom of the house before 
he had finished cementing the joints at the other extremity of the 
house. Like the painters, the plumbers assured me that the ad- 
mixture of white-lead or red-lead with the putty does not prevent 
mice from eating it. They hold that the best way of protecting 
their putty-joints is by binding a strip of thin sheet metal around 
the finished joints in such wise that the mice cannot get at the 
putty. . 
In the following experiments, which were continued during eight 
or nine months, the mice were kept in a small box 9 X 12 inches, 
placed in a comfortable room. Commonly, there were three of the 
animals in the box, new ones being introduced occasionally to 
replace those that perished. They were provided with cotton-wool 
for a nest, and with as much water as they wished. For several 
days after their capture they were given more oats than they 
could eat, but as soon as they had become wonted to the cage, 
the supply of oats was cut down to a quantity no larger than 
was suflicient to maintain the animals in good case,* and balls 
of putty made of whiting and raw linseed-oilt were daily placed 
in the cage. It was found immediately that the mice ate the 
putty freely and in quantities which must be regarded as very 
large when the small size of the animals is considered. For ex- 
sunple, three mice ate during terms of seven or eight days as 
many as 10 or 12 balls of putty daily beside their allowance of 
oats. The putty balls were just large enough to pass without 
touching through an auger-hole three-eights of an inch in diame- 
ter. Meanwhile the dung of the animals became perfectly white 
and of very large size, often more than twice as large as the 
ordinary dung of mice. 
At one time, in the month of February, after the mice had been 
fed upon putty, as above, for ten days, a special quantitative trial 
was made for the purpose of ascertaining the weight of dry whiting 
* Each mouse got 25 kernels of oats, amounting to 0.835 grammes, on the 
average, per day. 
+ Probably adulterated with fish-oil, as is the custom in this vicinity. 
