PREFACE. vii 



working out of: many complicated processes cannot 

 be attempted in a general course of this sort, but 

 must be done by the advanced student working in 

 the laboratory for several hours daily. The ex- 

 ceptionally high magnifying powers sometimes men- 

 tioned in the following pages, may be used by him, 

 but in the case of the beginner it is understood that 

 they are intended to be used for special demonstra- 

 tion by his teacher. 



In the course of the demonstrations (Part III.), 

 the student is desired to read the general considera- 

 tions regarding methods, in Part IV. ; and when he 

 finds no statement regarding the preservation of a 

 specimen, it is to be inferred that it is needless to 

 preserve it. 



In this edition, the book has been considerably 

 extended by an account of the microscope, and 

 fuller descriptions of the tissues. All figures of the 

 latter have been omitted, however, for they are to be 

 found in the systematic text books already in the 

 hands of everyone. Their repetition here would 

 therefore have entailed needless addition to the 

 expense of the work. It is hoped that the demon- 

 strations of the tissues, if made as directed, will 

 supply the place of pictures, and that the descrip- 

 tions will, together with hints from the teacher, prove 

 a sufficient guide to them. 



