110 TRANSACTIONS OF THE 



answering this question, I may state my firm belief that all organic 

 beings, whether belonging to the animal or vegetable kingdom, 

 require an occasional cross with another individual ; or, what is 

 the same thing, no hermaphrodite can fertilise itself for a perpetuity 

 of generations. It is well known to most people that flowers are 

 of the greatest necessity for the existence of insects; but it is 

 little known, on the other hand, how necessary insects are for the 

 existence of flowers. Many flowers in fact are entirely dependent 

 on insects for the safe carriage of the pollen of one flower to the 

 pistil of another, while in others which could fertilise themselves 

 it is of the greatest importance that we occasionally get a crossing 

 from one individual to another. Every person who has paid the 

 least attention to the breeding of animals knows the importance of 

 this fact. Well, it is of no less advantage to plants that the pistil 

 of one flower be fertilised by the pollen of another than it is to 

 animals that one animal should be fertilised by another animal 

 not closely related to it. 



If then it is advantageous to flowers that they should be visited 

 by insects, it will be evident to every one that those flowers which, 

 either by larger size, brighter colour, sweeter scent, or greater 

 richness of honey, were most attractive to insects, would, cceteris 

 paribus, have the best chance of living in the struggle for existence 

 that is going on among all members of the vegetable world. Sup- 

 pose a flower were to fertilise itself for any length of time, it would 

 become so weak that it would not be able to survive owing to this 

 continual war. It is a well-known fact that stock deteriorates 

 where the young are produced from parents of near kinship. 

 Similarly in the human family, intermarriage of near relationship, 

 i.e., when the degree of consanguinity is close, appears to exaggerate 

 in their offspring any diseases, whether nervous or otherwise, under 

 which their parents may have been labouring. 



Let it then be assumed that cross-fertilisation is advantageous, 

 and that " in and in " breeding does the greatest harm ; and of this 

 I think there is very little doubt. How then is the propagation 

 of plants insured ? 



For this, nature employs various means. 



First, she may develope the male and female organs on entirely 

 different flowers of the same plant, and to this the term monoecious 

 is applied. Again, she may develope the male organs on the flowers 

 of one plant and the female organs on the flowers of another plant, 



