34 MEMOIE OF ALFRED SMEE. [Chap. IV. 



disease, as it is a very good example of all of them. The lecture 

 clothed in its proper form will be found in the Appendix, No. 



XV.B. 



Insect Plagues. 800,000, St. Augustine. Barnes, 2000 miles 



covered by them. 

 Aphides. 

 Demonstration : 



1. Live plants. 



2. Healthy. 



3. Sucks juices. 



4. Impairs qualities. 



5. Alters properties. 



6. Bad sap not nourish. 



7. Imperfect tissue dies. 



8. Death local, remote. 



9. Remote death entirely HU the plant. 



10. "Wild plants resist better than cultivated. 



11. Cultivated plants iU resist. 



12. Deposition of fibre. 



13. Propagation of diseased fibre. 



14. Injury to plants hastens transformation. 



15. Growth of fungi. 



Destroyers of aphides — ^ladybirds, gauze- wings, synphidse, ichneumons, 

 Chalcididse, birds. 



Great fleas and little fieas have smaller fleas to bite 'em ; 

 These smaller fleas have lesser fleas, so on ad infinitum. 



Aphides live on all plants. 



Vastator potato no novelty. 



Gangrene. 



Vastator, name, leaf, root, history, anatomy, chemistry. 



Subsistence. 



Tendrils. Oxyhydrogen. Microscope. 



Future prospects, transitions. 



" I will rebuie the devourer for your sake, and it shall not destroy the 

 fi-uits of the ground." 



Whenever my father found a plant infested by an aphis, 

 he used to secure some specimens, put them in a pill-box, and in 

 the evening place them in Canada balsam so as to carefully 

 examine them. In this way he preserved all his evidences 

 upon this point for future reference, and the name of the plant 

 on which the insect fed was immediately scratched on the glass 

 with a diamond, so that no source of error could possibly arise. 

 The mode of fixing the insect in Canada balsam was very simple : 

 a slip of glass was warmed over a candle, and a drop of the 



