CARE AND RECORDING 477 



wire is nailed on the under surface of the frame to prevent the mice from 

 chewing the cover and the edges of the box. 



A cross-bar near the front on the covers supports the water bottle (16 oz.) 

 in a slanting position. A bent glass tube passing through a rubber stopper 

 extends from the water bottle down into the pen. The end of the gooseneck 

 is partially closed to form a nipple from which a drop of water hangs. There 

 is no leakage from the water bottle unless the opening in the tube is too large. 

 Ordinarily the bottles need to be filled no oftener than once a week. 



A hole is cut in the wire of the cover to receive the wire food hopper which 

 measures, at the top, 3X2 inches. At the bottom of the hoppers the 

 measurements are 3 X 1^4 inches. The wire from which the hoppers are 

 made has four wires to the inch and the parts are sewed together with fine 

 copper wire. The upper parts of the hoppers are bent so that they interlace 

 with the wire of the cover to hold the hoppers in place and prevent openings 

 through which small mice might escape. The hoppers extend to within an 

 inch from the floor of the cage and hold suf]ficient food to last six mice one 

 week. 



Several commercial foods in pellet form are available for use in hoppers 

 of this type. 



The type of rack which one uses is important from the standpoint of 

 cleanliness and the control of vermin. Metal racks are more satisfactory 

 from this standpoint than are wooden shelves. The clearance between 

 shelves should be at least 11 inches. The shelves may be 12 inches or 24 

 inches wide to provide space for one or two rows of boxes. In small quarters 

 the shelf space may be increased considerably by careful planning and the 

 use of certain types of racks. 



All boxes containing mice should be changed at least once a week. The 

 clean boxes should contain shavings or sawdust and a small amount of 

 cotton for bedding. Some stocks require shredded paper in place of cotton. 

 The soiled bedding in the used boxes should be entirely removed after 

 which the boxes should be thoroughly sterilized and dryed before they 

 are used again. The water bottles and covers should be washed at 

 intervals. 



The mice are marked by a series of holes and notches on the ears (Fig. 

 172). The units are recorded on the right ear, the tens on the left ear. 

 Number one, two and three are represented by holes at the front, top and 

 back respectively; four, five and six each by a single notch starting from the 

 front of the ear; seven is represented by two notches close together at the 

 front; eight by two notches at the top and nine by two notches at the back 



