INTRODUCTION. vn 



the matter is presented rather in the form of suggestions to those 

 who may be at the beginning of their work in micro-chemistry or 

 technique. 



The tests for the different vegetable substances and the gen- 

 eral properties of reagents have been taken from the best authori- 

 ties on those subjects, and carefully tested. 



I am responsible for the plan of the manual of directions 

 (Part II.), for some of its phrasiology, and for the selections of 

 most of the subjects used for study; and any imperfections in 

 this part must be laid at my door. Nevertheless the plan has stood 

 the test of many years thoughtful use in my own laboratory, and 

 more recently in that of Wabash College ; and Professor Thomas 

 shares completely with the writer the belief that such an element- 

 ary course, most thoroughly taught, should be made the founda- 

 tion for advanced instruction on the morphology of the higher and 

 lower plants, and should enter into the education of a student for 

 any independent work in anatomy, physiology, or biology. 



If other teachers should find the work acceptable, we would 

 remind them that a course of carefully prepared lectures should 

 supplement the laboratory work, and we urge them to so present the 

 subject, that the intergradations of tissues may not be overlooked, 

 and the larger relations of great tissue masses and their beautiful 

 adaptations to the necessities of the living plant, may be completely 

 understood by the student. No true teacher will allow a student 

 to consider these individual studies in an unrelated way. We 

 have cited freely text books and reference works of unquestioned 

 value, such as are to be found on the book-shelves of every good 

 laboratory, but we have not made a practice of referring to original 

 papers, as it would be for the most part out of place in a work of 

 this kind. But this does not release the teacher from the duty of 

 placing the most important papers bearing directly on a subject of 

 study within the reach of the student and requiring him to look 

 them over. 



The inconvenience of using plates placed at the end of a book 

 will not be great, and is offset by the fact that they are removed 

 from the unavoidable scrutiny of the student as he is executing his 

 own drawings, but any defect in this or any other direction noticed 

 and communicated by a teacher may be rectified in another edition. 



