EFFECTS OF DRUGS ON A\TiITE MICE 135 



again at the twenty-fifth week. Its maximum run was 149 307 

 revolutions at the fourteenth week, and its minimum run, 44 623 

 revolutions at the thirtieth week. Its average weekly run was 

 89 218 revohitions. 



Comparison of the weekly activity of all the mice 



Although all these mice were of the same sex, the same age and 

 closely related, yet even in the same lines they showed great indi- 

 vidual variations in their activity. 



Some time was necessary for the mice to get accustomed to the 

 cages. The first week's runs are low, although the animals had 

 been in the cages almost a week before the experiment was begun. 

 All but one of the mice showed their greatest activity in the early 

 part of the experiment. The decline in the latter part was prob- 

 ably due to increase in age. Slonaker ('07, '12) found that white 

 rats are most active in early life. 



The mice may be divided into two types, with one exception. 

 Type 1 had a period of high activity falling within the tenth to the 

 twenty-third week, and a second period of great activity occur- 

 ring between the twenty-fourth and the thirty-second w^eek. This 

 would seem to be normal. This group includes six mice, controls 

 Nos. 1, 2 and 4, nicotine Nos. 9 and 12 and caffeine No. 16. 

 These six mice were more active than any of the others. None of 

 them died. 



Type 2 exhibited only one period of high activity which fell 

 within the tenth to the twentieth week; the runs then decreased 

 steadily to the end of the experiment. This includes nine mice, 

 control No. 3, all of the alcohol mice, nicotine No. 10 and caffeine 

 Nos. 13, 14 and 15. Only one of these, alcohol No. 7, is above 

 the average in activity; all the others fall below the average. 

 Three of these mice died. It is evident that these mice had less 

 vitality than those of the first type. 



No, 11 of the nicotine line is an exception to these two types. 

 Its period of high activity did not begin until the twenty-eighth 

 week, and its maximum run came at the thirty-fifth week. 



