HEREDITY OF WILDNESS AND SAVAGENESS IN MICE 3 



tangular parallelepipedon, the truncation beginning at a line 

 in the top 8 cm. from the back side and extending to a Hne 

 in the front side 8 cm. from the bottom. The bottom of the 

 cage is 30 cm. long by 21 cm. wide; the back, 21 cm. wide by 

 21 cm. high; the portion of the top parallel with the bottom 

 and the portion of the front parallel with the back are each 

 8 cm. by 21 cm. The slanting surface comprising the remain- 

 ing part of the top and front is 26 cm. long by 21 cm. wide. The 

 two remaining sides of the cage are five sided, the measurements 

 of each being 30 cm. by 21 cm. by 8 cm. by 26 cm. by 8 cm. 

 In the slanting surface, 8 cm. from the top and bottom and 

 5.5 cm. from each side, is the door 10 cm. by 10 cm. The lid 

 is 12 cm. by 12 cm. hinged at the top. 



The very convenient watering system in use at the Bussey 

 Institute was also adopted. It consists of a 10 or 12 ounce 

 bottle fitted with a perforated rubber cork through which is 

 passed a small glass tube bent at an angle of about 120 degrees 

 so that when the bottle is placed upon the slanting surface 

 of the cage the tube will extend down through the wire of the 

 fore part of the cage to within easy reaching distance from the 

 floor of the cage. The lower end of this tube is slightly drawn 

 together so the water will not flow of its own accord. The 

 mice soon learn to drink drop by drop from the tube. Thus 

 there is a constant supply of clean water without the evil effects 

 of a wet cage as when the water is placed in a receptacle on the 

 floor or side of the cage. The bottle serves also as a weight 

 on the lid of the cage making it impossible for the mice to escape 

 in this way. 



When in use these cages were placed upon wooden shelves 

 w^hich were covered with sufficient sawdust to well cover the 

 bottom of the cage. This sawdust would remain on the shelf 

 when the cage was raised and so could be replaced with fresh 

 sawdust without greatly disturbing the mice. 



Shredded tissue paper was used as bedding for the mice and, 

 since it was the purpose of the experiment to minimize as much 

 as possible the effect of the presence of the experimenter while 

 cleaning cages, feeding or testing the mice, there was always 

 sufficient paper in the cage to enable the mice to hide in it if 

 they so wished. Until all the tests were made the mice were 

 seldom handled or otherwise greatly disturbed except when 

 being tested. 



