RELATION OF BURSARIA TO FOOD 



49 



50 - 



48 



46 



44 - 



42 



40 



38 



36 



34 



32 



30 



28 



I 26 



I 24 



f 22 



~ 20 



IS 



16 



14 



12 



10 



6 



6 



Fig. 7 Experiment XXVII. Curve .-1. course of extrusion of Chinese ink show- 

 ing two maxima (cf. fig. 6, curve ^1); curve B, that of complete digestion, by the 

 same individuals used in curve A, of extracted yolk; curve C, control: course of 

 extrusion of ink by forty-eight individuals fed ink alone. 



ill this curve, and this comes about eighteen hours later than the first 

 maximum of curve .4 and at about the same time as the second maxi- 

 mum of B. The significance of the second maximum in curve A is 

 brought out in the following analysis of the two curves A and B., that 

 is, in a quantitative analysis of the reactions of the forty-eight indi- 

 viduals used in the experiment. All the individuals which at any of 

 the examinations had ink and j^olk present in the same vacuole, or 

 vacuoles, were recorded, hence we have a means of dividing the forty- 

 eight individuals into two groups. Group I is made up of those in 

 which, throughout the experiment, yolk and ink were in distinct and 

 separate vacuoles, while Group II, includes those which had during 

 part or all of the time one or more vacuoles which contained both ink 

 and yolk in the same vacuole or vacuoles. Now we have the data 

 which will show just what relation ink and yolk have to each other in 

 the cytoplasm of Bursaria, and what the reaction of the cell is toward 

 each of the two conditions represented by the composition of the vacu- 

 oles of the two Groups I and II. 



THE JOURNAL. OP EXPERIMENTAL ZOOLOGY, VOL. 16, NO. 1 



