PRESIDENTIAL ADDRESS. 15 



the careful and methodical selection of man. Another 

 example is taken from the vegetable kingdom. Certain 

 plants secrete a sweet juice apparently for the purpose of 

 eliminating injurious matter from the sap. This is 

 effected by glands or nectaries, such as can be seen by 

 the microscope on the backs of laurel leaves, and in the 

 less accessible parts gf flowers. These juices are eagerly 

 sought by insects which, while gathering them, are dusted 

 by the pollen, and transmit the latter from flower to 

 flower. Two distinct individuals would thus get crossed, 

 the act of crossing being known to give rise to the most 

 vigorous seedlings, which would consequently have the 

 best chance of surviving. Those with the largest nectaries, 

 by secreting most nectar, would be the oftenest visited and 

 crossed. Somewhat similar would be the effect upon the 

 insects depending upon nectar for food. A bee or other 

 insect with a slightly lengthened or curved proboscis 

 would more easily obtain food than others, and thus the 

 communities to which they belonged would flourish and 

 give rise to swarms possessing the same peculiarities. 



The subject of the fertilization of plants has had an 

 entirely new interest imparted to it by Darwin's researches. 

 It was until recently believed that self-fertilization between 

 the stamens and pistils in the same flower was the rule 

 rather than the exception, but from the beautiful and 

 striking instance of the primrose, Darwin exemplified 

 the truth that cross fertilization is not only beneficial but 

 may even be essential to plant life. 



In one common variety of the primrose the stigma of 

 the pistil overtowers the stamens, rendering self-fertiliza- 

 tion impossible ; in the other equally common variety, the 

 reverse order obtains. Bat, in the first instance, the 

 stamens being the lowest, the tip of a bee's proboscis is 

 dusted by the pollen as it searches for nectar, and the bee, 



