THE BREEDING OF MICE IN LABORATORIES 57 



2^ inches into the can. The edge of the wedge rests upon the 

 floor of the can and its sides extend outward on either side 

 of the opening from which they are about \ inch distant 

 laterally at the opening. 



The cage is small enough so the hind quarters of the adult 

 mouse must remain outside the can while its hind feet rest on 

 the edge of the entrance. These features prevent both fecal 



Fig. 11. Sectional view of feeding can. 



contamination and the kicking of food out of the can. The 

 mesh of the screen-wire wedge is fine enough to prevent dry 

 ration containing rolled oats from sifting into the feeding 

 chamber. The mouse simply reaches through the mesh and 

 pulls down what food he desires, eats it in place, and backs 

 out of the feeder when satisfied. If it is desired to give the 

 Maynard ration in the closed feeder, it should be mixed in 

 equal parts with rolled oats, because the Maynard ration is 

 finely ground and sifts through the screen wire. 



