vi PRKFACK 



have found this plan to be the most satisfactory in 

 practice. 5. To give drawings and diagrams of difficult 

 dissections, and of details which the beginner cannot as 

 a rule make out satisfactorily for himself ; but otherwise 

 to limit the number of illustrations so as not to tempt 

 the student to neglect observing the things themselves. 

 6. To include a short account of methods and technique, 

 limited to the barest essential outlines, sufficient for a 

 student working by himself to make out the things 

 described, but not going into such details as would 

 naturally be learnt in a properly organised laboratory. 



In the meantime, my brother had in preparation a 

 Biology for Beginners, in which he intended to carry out 

 the plan, suggested in the preface to his Elementary 

 Biology, of giving a simple account, with practical 

 directions, of one of the higher animals and one of the 

 higher plants, as an introduction to the study of 

 Biology. The animal he selected was the Frog, and 

 the manuscript of the greater part of this section of 

 the book was already finished and the rest in rough 

 draft. He had previously suggested that some of this 

 work might be utilised for our proposed Practical 

 Zoology ; and I found that, with certain additions and 

 with modifications in the arrangement, the whole of it 

 was exactly the kind of introduction I had in view for 

 the first part of our book. Some of the illustrations 

 that my brother had intended to insert in the Biology 

 for Beginners I have found it advisable to omit, and even 

 now tin- figures in the introductory part are purposely 

 nearly as numerous as those in the rest of the book. But 

 apart from these various minor modifications, Chapters 

 I Xfl in Part I are almost entirely taken from my 

 brother's manuscript. 



\W felt that there could be no object in entirely re- 

 writing the descriptions of several familiar animals 



