4. The following misprints have been corrected: "intellegently" corrected to "intelligently" (page 5) "basterial" corrected to "bacterial" (page 9) "would would" corrected to "would" (page 11) "natuer" corrected to "nature" (page 15) "Abilty" corrected to "Ability" (page 17) "Baillet" corrected to "Balliet" (page 17) "taht" corrected to "that" (page 22) "modificacations" corrected to "modifications" (page 24) "succes" corrected to "success" (page 26) "in" corrected to "In" at start of sentence (page 26) "fialures" corrected to "failures" (page 26) "toworrow" corrected to "tomorrow" (page 28) "Teahcing" corrected to "Teaching" (page 30) 5. Some of the punctuation errors, e.g., comma instead of period, extra period, etc. in the original have been silently corrected while those requiring interpretation have been left as such. 6. The titles listed in the table of contents do not match with the headings in the original text. However, no changes have been made in this e-text for these mismatches. 7. Other than the corrections listed above, printer's inconsistencies in spelling and punctuation have been retained.