238 THE PLANT WOELD 



We desire to testify to our appreciation of the letters we have re- 

 ceived commending the neat appearance of our reprint of volume I No. 

 1 of the Asa Gray Bulletin. We trust that those who have received 

 copies will not be remiss in forwarding payment promptly. The close 

 of a year, with the necessary indexing, purchase of supplies, etc., brings 

 heavy expenses to all publishers; and this year we are planning some- 

 thing in the way of a New Year's gift to our subscribers to signalize 

 the opening of our fifth year. 



The editors of this journal desire to enter a respectful but vigorous 

 protest against the use, by plant ecologists, of the term " plant-forma- 

 tion," This term has become so firmly fixed in geology and paleontol- 

 ogy that it is an integral part of its literature, and ought not to be dis- 

 placed or rendered ambiguous. A plant-formation, therefore, is prop- 

 erly a geological horizon which is marked or characterized by the pres- 

 ence of fossil plants. A " plant-formation " of the ecologist is simply a 

 plant society or association characterized by the presence of certain 

 living ^plants growing under similar conditions. 



BOOK REVIEWS. 



L Manual of Determinative Bacteriology, By Fred, D, Chestel'. 

 Octavo, pages vi-401, figs. 13. New York, MacMillan & Co., 1901, 

 Price $2.60, 



The author informs us in the preface that this work was the out- 

 come of a study of the bacterial flora of cultivated soils. On account 

 of the great amount of labor involved in compiling and collating the 



