BOTANY 



C. STUART GAGER 

 Formerly Professor of Botany 



Let me invite you this morning to take a walk with me, 

 in imagination, through the trees at the northern end of the 

 campus. If you are accustomed to observe what is going on 

 about you, you will notice that, as you walk northward, the 

 tree-trunks appear chiefly of a sombre, brownish color, but, 

 as you walk southward, the northern aspect of the tree trunks 

 is a beautiful leaf-green. Did you ever notice this phenom- 

 enon before your attention was called to it; and now that it 

 is brought to your notice does it arouse on your part any 

 real desire to know the why and the wherefore? If not, then 

 you may rest assured that nature never intended you to be a 

 botanist, for, as the great French botanist, Augustin Pyramus 

 DeCandolle, wrote in 1832, "The interrogation point is the 

 key to all the sciences," 



Let us, then, interrogate more closely the northern side 

 of one of the three-trunks. The green color is seen to be 

 due to the presence of a greenish substance which, in rela- 

 tively dry weather, may be brushed off as a fine powder. 

 The unaided eye can discern nothing more; but, if we carry 

 a sample of this substance to the laboratory and examine it 

 under the compound microscope, we shall find that it is made 

 up of countless little spheres. Some of them are perfect in 

 shape, others appear constricted as if dividing, others just 

 barely connected in the last stages of division, and still others 

 adhering together in groups of two or more. Where they 

 touch they are flattened, but otherwise they are nearly per- 



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