36 



E. J. LUND 



Experiment XVIII. The two dishes A and B in Experiment X\'I1 

 (b) were left standing for two hours; then they were Avashed once and 

 tested with the same material used in Experiment XVII (b), in order 

 to show the effect of the adsorption of the liberated stain by the un- 

 stained grains mixed with the stained ones. Time of feeding fifteen 

 minutes (table 20). 



This shows that when the janus green yolk is left with the un- 

 stained yolk for some time, the liberated stain from the janus 

 green yolk is adsorbed by the unstained yolk grains, and as a 

 result the latter are not eaten so readily. If the mixture is left 

 standing too long and then rinsed in tap water, then no grains 

 are eaten. Bursaria can react to such small quantities of ad- 

 sorbed janus green that the amount adsorbed cannot be dis- 

 tinguished by the eye, when the unstained yolk grains mixed 

 with the stained ones are examined. 



Experiment XIX. To prove that the solution of the janus green 

 which is produced by the liberation of the stain from the stained yolk, 

 does not even in quite strong concentrations prevent the eating of 

 fresh yolk placed in it, the result of one test out of a considerable num- 

 ber made at different times, is given. A solution was drawn off from 

 janus green stained yolk used in an experiment in which no grains of the 

 mixture had been eaten, after standing for some time. To this solution 

 was added unstained yolk. Ten individuals were tested (table 21). 



TABLE 21 

 Experivienl XIX 



