THE PEINCIPLE OF COHESION. 



71 



appeared, d represents a section of two-thirds of the height 

 of the infei-ior ovary; but now the fibro-vascular cylinder 

 is dissociated, and forms fifteen separate cords — two being 

 marginal to each placenta and one belonging to each septum. 

 As the cords have their spiral vessels reversed in position, 

 i.e. facing outwards and not inwards towards the centre, 

 their axial character has ceased.* 



iij^ 



a - d 



Fig. 15. — Campanula medium (after Van Tieghem). 



The rule appears to me to be that as soon as, or even 

 before tbe level of the insertion of the ovules is reached, the 

 internal position of the tracheaa is abandoned. This is the 

 case with Lychnis. 



In some cases there is an apparently axial formation, 



* I do not find that matters can be really expressed quite so "diagram- 

 matically " as, e.g., in his figure d; for Van Tieghem does not pay much 

 attention to the central and scattered positions of the trachea;, which I 

 take to be quite as significant as their outward orientation ; for as the 

 ovules are approached they become dispersed, though a medulla remains. 



