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magnifying of trifling distinctions due to want of education and of 



pliilosophieal views . ... 13 



Physiology, evil of studying without preliminary acquaintance with 

 System, etc. — Defective state of modem botanical instruction, and 

 its effects — The value of the study of System evidenced in Whewell's 

 1 History of the Inductive Sciences' — The greatest discoveries in 

 physiological botany developed through the labours of great Sys- 

 tematists, Linnaeus, Brown, and Brongniart . . . . .14 



Relative importance of elementary acquaintance with physiology in 

 Animal and Vegetable Kingdoms — Obstacles at outset to students 

 acquiring an elementary knowledge of botany and of botanical ter- 

 minology — Hence necessity of artificial systems for beginners . 15 

 Vulgar errors more habitual in all that regards the organs of plants 

 than of animals — Requirements for study of Systematic Botany, 

 especially development . . . . . . . . .16 



Necessity of comprehensive knowledge of forms and development im- 

 plies variation — Amount of variation can only be appreciated by 

 consideration of these — Physiology, as a branch of botany, evil of 

 misunderstanding its relation to other branches of the science . 17 

 Practical advantages of the study of classification — Defective prelimi- 

 nary education of men intended for scientific professions . . 18 



III. Subjects op Variation, Origin of Species, Specific Centres, 



Hybridization, and Geographical Distribution . . .19 



Desirability of explaining the principles adopted by naturalists — Vague 

 and unphilosophical use of the word Species . . . . .19 



Differences of opinion upon the subject — Lamarck — c Vestiges of the 

 Natural History of the Creation' — Sir 0. LyelTs writings — Our own 

 views — Prevalence of doctrine of mutability due in part to faulty 

 education ........... 20 



Hypothesis of non-existence of species does not diminish the value of 

 the study of Systematic Botany— Necessity in that case of explain- 

 ing the laws that govern the relative mutability and permanence of 

 forms ......... .21 



A. Effects of Hybridization, 



Difficulties attending the operation 



21 



Its partial effect 



en to narents. and 



barren 



■Analogy from animal kingdom— Garden 



existence 



ture ; necessity of arguing from such facts on broad principles, and 



.1- A *. ... P 1_ 1 ' T . • ,-.. - _ - - 



argum 



species 



22 



informatio 



uments 



The 



23 

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