ANDEBSON'S PRACTICE. 491 



ground, he win have them put into pots, and removed xtnder glass, so 

 as to escape the accidents of variable temperature — of wind, rain, and 

 dust, and, ahove all, of insects. A greenhouse fully exposed to the 

 sun is best adapted for the purpose, at least as regards hardy and 

 proper greenhouse plants. Having got them housed, secure a corner 

 where they are least likely to be visited by bees or other insects. The 

 plants which are to yield the pollen, and the plants which are to bear 

 the seed, should be both kept in the same temperature ; but where this 

 cannot be managed, pollen from an outside plant, in genial summer 

 weather, may be used, provided it can be got ; for there is a class of 

 insects which live exclusively on pollen, and devour it so fast after the 

 pollen vessels open, that, unless the plant is under a hand-glass (which 

 I would recommend), it is scarcely possible to get any pollen for the 

 required purpose. To secure against chances of this nature, a sprig 

 with opening bloom may be taken and kept in a phial and water inside, 

 where it will get sufficient sun to ripen the pollen. But here, too, 

 insects m.ust be watched, and destroyed if they intrude. An insect 

 like, but smaller, than the common hive bee, which flits about by fits 

 and starts, on expanded wings, after the manner of the dragon-fly, is 

 the greatest pest, and seems to feed exclusively on pollen. The hive 

 bee, the humble bee, and wasp, give the next greatest annoyance. All 

 these may be excluded by netting fixed over apertures from open 

 sashes or the like. Too much care cannot be bestowed on excluding 

 these intruders, whose single touch, in many cases, might neutralise 

 the intended result ; for the slightest appilication of pollen native to the 

 parent plant is said by physiologists to supersede all foreign agency, 

 unless, perhaps, in. the crossing ef mere varieties ; and the truth of 

 this observation consists with my own experience. Without due pre- 

 caution, now, the labour, anxiety, and watchfulness of years may 

 issue in vexation and disappointment. As a further precaution stUl, 

 and to -prevent self -fertilisation, divest the blooms to be operated on 

 not only of their anthers, but also of their corollas. Remove also all 

 contiguous blooms upon the plant, lest the syringe incautiously 

 directed, or some sudden draft of air, convey the native pollen, and 

 anticipate the intended operation. The corolla appears to be the 

 means by which insects are attracted ; and though, when it is removed, 

 the honey on which they feed is stiU present, they seem puzzled or 

 indifferent about coUeoting it ; or if, haply, they should alight on the 

 dismantled flower (which I never have detected), the stigma is in most 

 cases safe from their contact. It will be some days — ^probably a week 

 or more, if the weather be not sunny — ere the stigma is in a fit condi- 

 tion for fertilisation. This is indicated in many families, such as 

 Ericacese, Eosacese, Sorophularinse, Aurantiacese, &o., by a viscous 

 exudation in the sutures (where these exist) of the stigma, but gene- 

 rally covering the entire surface of that organ. In this condition the 



