RELATIONS OF BURSARIA TO FOOD 17 



removed from the dishes with tap water, and two individuals were 

 placed in each watch glass in order to lessen the labor in taking 

 the records. Each watch glass contained 2 cc. of tap water. 

 The watch glasses were placed in moist chambers. In order to 

 avoid the effect of individual variations in the rate of digestion 

 of equal numbers of grains, forty-eight individuals were used 

 in each set. Effects upon the result due to variation in size of 

 the grains were therefore also practically avoided. Digestion 

 was taken to be complete when all the solid contents of the 

 vacuole had become luquefied. The results of two experiments 

 are given. 



Experiment III, February 12, 1913: Table 3. Each individual of 

 Set A, Set B and Set C was fed 1, 3 and 6 grains respectively. Exami- 

 nation of each individual was made and records taken, 3^, 5, 6|, 8, 9|, 

 11, 12|, 14 and 22 hours from the time of feeding. 



The rate of digestion and resorption when a large number of 

 grains have been fed is in many cases slow toward the end of the 

 process; so that it is sometimes difficult to tell at just what time 

 (within 1 or 1^ hours) the last remains of solid protein disappear. 

 For this reason eighteen hours was taken as the average time of 

 complete digestion in those individuals of Set C which had small 

 protein residues at the end of fourteen hours and none at twenty- 

 two hours. All of Set C showed complete digestion at the end of 

 twenty- two hours., 



In each of the three sets (table 3) individuals numbered 2 show 

 a longer time for digestion than their partners numbered 1. 

 This has no significance, because it is due to arbitrarily calling 

 the first individual that had completed digestion, number 1, and 

 the last one, number 2; when the record was taken. The same 

 is true for table 4, Experiment IV. 



It will be seen from table 3 that the average number of hours 

 which it takes to complete digestion in the three sets A, B and C, 

 is not directly proportional to the number of grains eaten, i.e., 

 as 1:3:6. Before further consideration of these results the next 

 experiment will be described. 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 17, NO. 1 



