iv PREFACE. 



" Versuche " of 1893, in MacDougal's "Experimental Physi- 

 ology ' in 1895, and in Darwin and Acton's "Practical 

 Physiology' in 1896. Several of these works have passed 

 to later editions, and to translations. A number of contribu- 

 tions to the simplification of appliances have appeared in the 

 Botanical Gazette, notably by Arthur (in 22, 463), by Barnes 

 (in 12, 150), by Copeland (in 26, 343; 29, 347, 437), by 

 Stevens (in 20, 89), by Stone (in 17, 105; 22, 258), by the 

 present writer (in 27, 255), and by others, all of which are 

 mentioned in their appropriate places in the following pages. 

 To these should be added Hansen's papers in Flora, 84, 352 

 and 86, 469. I have made much use also of two small works, 

 which, not having been regularly published, are not included 

 in the bibliography on a later page, namely, Arthur's " Labora- 

 tory Exercises in Vegetable Physiology ' (Lafayette, Indiana, 

 Kimmel & Herbert, 1897), and MacDougal's "Plant Physi- 

 ology: Directions for Practical Work ' (privately printed, 

 Minneapolis, 1897). 



It is my pleasant duty to state here that the book has the 

 great advantage of having been read and criticised in manu- 

 script by Professor Charles R. Barnes of the University of 

 Chicago, to whom I make my grateful acknowledgment. 

 Most of Professor Barnes's suggestions are embodied in the 

 following pages, but he must not be held responsible for 

 approval of all in the book, since in places where we differed 

 in opinion I have followed my own inclinations, perhaps to the 

 detriment of the work. I have also to thank Mr. E. J. 

 Canning, Head Gardener at Smith College, for his constant 

 and skilled assistance in everything relating to the cultivation 

 of materials for the course. 



