78 



CARNEGIE INSTITUTION OF WASHINGTON. 



between the funicles, along these and along the surfaces of the ovules 

 to the micropyle with little indirection. Passing down the micropyie 

 with no destruction of tissues, the tube reaches the egg. The course 

 is therefore ectotropic, a point of importance to be considered when 

 ovarial treatment is used for inducing changes in the organism, and 

 which, in view of the facts derived from work on other Gamopetalse,^ 

 must be determined in each particular instance. 



Fifteen hours after the injection of the reagent into the ovary (the 

 wound lying within the placenta except at its upper end) the interior 

 cells (but not the epidermis of the placenta and funicles) were fairly 

 deeply stained. Though in some instances there was no visible trace 

 of the dye in the body 



of the ovule, the fact /^\r^?i:5^ti>Y^c/^aZ 



that dead nucellar or 

 antipodal cells were 

 very deeply colored 

 showed that it had 

 spread farther than 

 was evident to the eye. 

 Other ovules showed a 

 faint but quite distinct 

 coloration of the walls 

 of the nucellar cells, 

 while in these or other 

 ovules a portion of the 

 tapetum and the em- 

 bryo-sac structures, in- 

 cluding the egg-appa- 

 ratus (or sometimes 

 this alone), also re- 

 vealed color. The 

 same relations were 

 shown by ovules 24 

 hours after treatment, 

 but in a more pro- 

 nounced degree, due (in 

 the instance in ques- 

 tion) in part to the fact 

 that the fluid found its way into the ovarial cavity. Preparations 

 allowed to remain for 44 hours after injection again showed deep stain- 

 ing only of the funicle, raphe, and nucellus, a few ovules alone showing 

 any color in the embryo-sac and none in the tapetum. 



These relations of the ovular tissues to the stain were substantiated 

 by placing sections of the living ovary in a weak solution of the reagent 



'Lloyd, Mem. Torr. Bot. Club, vol. 8, and elsewhere. 



Fig. 3. — Longitudinal section of an ovule of Scrophularia 

 (slightly diagrammatic), to illustrate the course of methy- 

 lene blue and the selective action of the nucellus (nuc.) 

 and tapetum (tap.); ant., antipodal cells; chal., chalaza; 

 end., endosperm; fun., funicle; ovum, or egg-cell; raphe, 

 the conductive tissue extending from the funicle to the 

 chalaza. (Drawn by F. E. Lloyd.) 



