16 . W. P. Wilson. 



Experimental Part. 



Arresting of the Secretion of Nectar by Washing, on the 

 Nectaries of Fritillaria imperialis. 



A slem of Fritillaria imperialis with three flowers, the youngest not 

 yet opeD, but with nectaries just l)eginning to excrete, the second two 

 thirds open, nectaries active, the third flower just fully open and nectaries 

 filled with fluid, was taken for this experiment. 



The nectaries were all washed thoroughly by means of a wash-bottle, 

 afterwards dried with bibulous paper. It was necessary to open the bud 

 to receive the first washing. 



The nectaries of the youngest flower were washed four times, those of 

 the other two three times during a period of three days. This was suffi- 

 cient to stop all further flow of nectar. During the experiment the flowers 

 were kept under a bell-jar in a meist almosphere. At the end of the three 

 days the flowers were still all fresh and young. None of the anthers were 

 open. Such flowers, when left to their natural course of development ex- 

 crete nectar for a period of frora eight to ten days. When the nectar is 

 removed with a pipette and the surface of the nectary left meist there is a 

 quick return of the fluid. This is caused by the Solution which remains on 

 the surface and also fills the interstices of the outer cell-walls of the epi- 

 dermis. It is easily understood that a constant removal of this Solution 

 with a pipette may in time so dilule the same as to stop the flow of nectar, 

 Two causes may here be mentioned which are able to keep the nectary in a 

 State of activity. 



First: the constant evaporation of water which often reduces the 

 nectar to a thick sirup, thus making the osmotic action much strenger than 

 it otherwise would be ; and second : the probable production for a consid- 

 erable length of time in some cases, of a fluid by disorganization of the 

 cell-walls. 



In order to illustrate the difFerence belween old and young nectaries 

 in the continuation of the excretion, a flower from Fritillaria imperialis was 

 selected in which the poUen was fully ripe, the anthers having already 

 opened. 



After carefuUy washing and drying the nectaries once the flower was 

 placed in water under a bell-jar. The nectaries conlinued to remain per- 

 fectly dry. 



