TABLE OF CONTENTS 



PAGES. 



Introduction 375 



1. The Use of Other Species 378 



2. The Original Plant 380 



Original Habitat 380 



Introduction to Cultivation 380 



Two Varieties Introduced 382 



3. The Modern Plant 385 



Structure and Characteristics 385 



Varieties of To-day 387 



Modern Potato Breeders 390 



4. Methods of Breeding 391 



General Basis 391 



Precautions in Comparative Tests 394 



Correlations 395 



5. The Inheritance of Characters in Tuber Selections 398 



Theory 398 



Experimental Evidence 403 



6. Hypothesis of Degeneration 410 



Analysis of the Question 410 



Biological Evidence 413 



Experimental Evidence . . . . 414 



7. Discontinuous Variations 417 



8. Graft Hybrids 418 



9. Quality 419 



Historical .. , ; 419 



Sxperimeblajlx*: ;,.- 422 



A I .** Qomposition . ..Different Parts 422 



' ' * *' : "Sahlplmg**.. /.;,..! 423 



Relations Between Total Nitrogen Content and 



Quality 423 



Relations Between Dry Matter and Quality 425 



Physical Structure and Quality 426 



Other Factors Influencing Quality 429 



10. Variations in Chemical Composition as a Basis for Im- 



provement 437 



Selections for Planting in 1902 439 



Selections for Planting in 1903 443 



11. General Statements 447 



Bibliography 450 



