BOOKS AND CURRENT LITERATURE 207 



stimulate speculation in the changes undergone by the cell walls during 

 temporary and permanent enlargement of the cells, and it is to be hoped 

 that they will also stimulate investigation on the same subject. Almost 

 nothing is known of the chemical and physical properties of the cell 

 wall and the alterations occurring in these properties under the influ- 

 ence of environmental conditions. The relatively great rapidity with 

 which the walls must be altered during reactions like those of Drosera 

 and Dioncea maj'' render these plants suitable experimental subjects 

 for certain phases of these problems. 



In the case of Drosera the rate of transpiration appears to control 

 its habit to a large extent, the low rosette appearing only with a rela- 

 tivelj' dry aerial environment. Prolonged high humidity is followed 

 by more extensive elongation of the stem, the development of smaller 

 leaves and by the loss of the red color. That a diminished transpira- 

 tion rate is directly responsible for all these changes is not maintained 

 by the author, for light and temperature were also altered when the air- 

 humidity was raised. Lack of animal food produces a disappearance 

 of the red pigment which may reappear within two days after the 

 plant is suppHed with insects. — H. E. Pulling. 



Diseases of Cultivated Plants. — There has recently appeared a 

 second edition of Massee's Diseases of Cultivated Plants and Trees, ^ 

 which differs from the first edition published five j^ears before only in 

 the addition of a sixteen page supplement. This supplement contains 

 accounts of diseases not included in the main body of the text, to- 

 gether with more recently acquired facts relative to the nature of 

 certain diseases. 



No name is so universally familiar in mycological literature as that 

 of the author and probably no one has succeeded in bringing together 

 so large a compilation of mycological facts as he. The present volume 

 finds its most useful purpose in its vast assemblage of data, which makes 

 it serviceable as a general reference work. The wide scope of the book 

 can be known from the fact that consideration is given in the first 

 eighty-seven pages to such subjects as epidemics, infection, dissemina- 

 tion, injuries brought about by drought, frost, hail, smoke, gas, etc., 

 fasciation, bacteriology of the soil, fungicides, spraying, phanerogamic 

 parasites, and the nature of fungi. The remainder of the book deals 

 with plant diseases in Great Britain, Continental Europe, together with 

 certain of those in the tropics and the United States caused by fungi, 



^Massee, G., Diseases of Cultivated Plants and Trees. Pp. 618, figs. 173. 

 The Macmillan Company, 1915. 



THE PLANT WORLD, VOL 19, NO. 7, 1916 



