RATIO OF TOTAL ACTIVITY 1 7 



a great deal, apparently in search for what they desired. The behavior 

 of the vegetarians strongly supports this supposition. When they were 

 fed they ate ravenously, as if they had been starving. This was not 

 so manifest in the omnivorous. It was true that both classes of exer- 

 cised rats always appeared more hungry than the control rats of the 

 same group. 



After the third month the general average of the vegetarians falls 

 below that of the omnivorous. This is shown in the curves of Figure 12. 

 Here we see that the omnivorous female rapidly surpasses the omni- 

 vorous male in the amount of work done. The female vegetarian also 

 excels the male of the same class in the distance run, but only to a small 

 extent. The females are thus voluntarily more active than the males. 

 We also note that the omnivorous male is much more active than either 

 sex of the vegetarians. At the time of the death of the vegetarian rats 

 (twenty-five months) the omnivorous female had voluntarily dome 

 almost nine and one-half times as much work as the female vegetarian, 

 and the omnivorous male almost three and one-half times as much as 

 the male vegetarian. 



When the total amount of work voluntarily done by each class is 

 considered, a still greater difference is observed. The omnivorous fe- 

 male ran a total distance of 5447 miles, while the vegetarian female ran 

 only 492.1 miles, or a ratio of about 11 : i. The omnivorous male ran 

 1588 miles, compared to 450.9 miles for the vegetarian male — a ratio 

 of 3.5 : I. The average run for both sexes was, for the omnivorous rats 

 3517.5 miles, and for the vegetarians 471.5 miles, or a ratio of almost 



7.5 : I- 



We thus see that when the initiative and ability to do work are 

 considered, the result is decidedly in favor of the rats that had received 

 animal food in their diet, and overwhelmingly against the vegetarians. 



The curves of Figure 12 show in a general way the rate at which 

 the life's work was accomplished by each rat. But to show this more 

 clearly Table VI has been constructed. The total average work for 

 each sex in the two groups was arbitrarily divided into eight equal parts. 

 Then the per cent of average lifetime required to do these fractional 

 parts was computed; also the average age in months equivalent to this 

 per cent is given. For example, when the omnivorous male had done 

 one-eighth of its total life's work it had lived 16.1% of its average life- 

 time, and had reached the average age of 4.5 months. This table shows 

 that the males of each group turn off their work at a relatively earlier 

 age than the females on the same diet. As an illustration, when the 

 omnivorous male had done one-half its life work it had lived 36.4% 



