206 On the Chemical and Natural History of Lupuline. 



small globules of essential oil ; it frequently happens that 

 these globules, by uniting, form a globule somewhat large, 

 which is very well seen on the summit of the grain in front 

 of the rent. 



This rent is generally made at the junction of the cuticle 

 with the edge of the cupule. The cuticle is raised, as a 

 cover, and, as the cupules open, the cuticle is detached, and 

 swims away in the surrounding liquid. Occasionally during 

 this action it occurs as much in the wall of the cuticle as 

 in that of the cupule, according to their greater or less re- 

 sistance. 



An alkaline solution and alcohol act more rapidly than 

 water, because, by dissolving more readily the resinous 

 matter which impregnates the walls of the grains, they 

 render the penetration more easy. 



It has never been possible for me to observe the pre- 

 tended pollen tubes seen by M. Kaspail, in examining the 

 fresh lupuline. But if we examine lupuline that has been 

 kept for some time, we observe a very few grains wdiich are 

 with difficulty impregnated with liquid in this or that place, 

 and which, breaking a long time after most of the others, 

 permit the exudation of a viscid matter. This matter, 

 moulding itself in the aperture which gives it passage, 

 slightly resembles, to a certain extent, a pollen tube, and 

 it was this most probably that was seen by M. Easpail ; 

 but it requires only a slight examination to account for the 

 appearance, which is most certainly due to the interior 

 matter of the grains having been dried dissolving with 

 difficulty. 



The lupuline is produced on the ovaries, on the inferior 

 surface of the bracts and on that of the leaves. It is equally 

 met with on the stem and on the stipules ; but it is only 

 on the ovary and on the scales of the cone that the lupu- 

 line arrives at its complete development. On the leaves, 

 on the stipules, and on the stem, it is never met with ex- 

 cept in the state of cupules more or less advanced, or all 

 simply of discs, which readily wither up and are shed. 



The lupuline is then a gland, which contains a complex 

 liquid, of which we now proceed to investigate the nature. 



