Originally published in 1896. PREFACE: The series of papers collected in this volume may be considered as a complement or commentary to my Essay on Classification since I have endeavoured to present here in a more popular form the views first expressed in that work. And although the direct intention of these pages has been, as there title indicates, to give some general hints to young students as to the methods by which scientific truth has been reached, including a general sketch of the history of science in past times, yet I have also wished to avail myself of this opportunity to enter my earnest protest against the transmutation theory, revived of late with so much ability, and so generally received. It is my belief that naturalists are chasing a phantom, in there search after some material gradation among created beings, by which the whole Animal Kingdom may have been derived by successive development from a single germ, or from a few germs……Many of the earliest books, partic