• BOTANY. 553 



ject is presented in the form of twenty-two lectures. The first eleven 

 treat of the physiological organography of the organs of vegetatiou j 

 the next two lectures treat of the general vital conditions and proper- 

 ties of plants ; and the remainder of the book is devoted to the subject 

 of nutrition, which will be continued in the next volume. The second 

 part of Detmer's System der Pflanzen-Physiologie, published in Schenk's 

 Eandhuch, is devoted to the physiology of growth. The continuation 

 of Van Tieghem's work, Traite de Botaniqiie, contains a large amotint of 

 information on physiological subjects. 



The subject of the action of light on plants and the relations of 

 chlorophyl to the plant economy has not occupied the attention of 

 botanists to the same extent that it did during 1881, although several 

 papers have appeared this year on the subject. Dr. Adolph Hansen, 

 in his doctorate thesis at Wiirzburg, called in question the correctness 

 of the views of Pringsheim on the nature of hypochlorin and its re- 

 lation to chlorophyl, and his paper was published at Leipsic this year. 

 Pringsheim in consequence addressed a circular to the philosophical 

 faculty of the University of Wiirzburg in support of his views, and this 

 circular, which is of a personal character, was embodied by him in an 

 article on GJilorophyllf unction und Lichtwir'kung in der Fflanze, published 

 in Pringsheim's Jahrhuch. The paper includes a summary of the views 

 of botanists up to the present day on the subject of assimilation. 

 Arthur Meyer, in the Bot. Zeitung, has a paper on the nature of what 

 Pringsheim calls hypochlorin-crystals.and another in the Centralblatt on. 

 chlorophyl- grains, starch-builders, and chromatophors. A summary 

 of recent works on the nature and function of chlorophyll is given by 

 Bonnier in the Annales des Sciences. Pringsheim's Jahrhuch contains 

 a lengthy paper on i^lant respiration by Godlewski. Schimper has a 

 paper on Oestalten der StdrTcebilner und FarhJcorper in the Centralblatt. 



The accuracy of Darwin's views on the action of the root- tip, advanced 

 in his "Power of Movement in Plants," had been called in question by 

 Wiesner, and this year two pupils of Wiesner, Burgerstein and Toma- 

 schek, have published articles on the sensitiveness of the root-tip, in 

 which they agree with Wiesner in believing that there is no intrinsic 

 power in the tip by means of which it tends to grow away from an object 

 pressing against it. Kirchuer, on the other hand, in studying the same 

 subject, thinks that the conclusions of Darwin are correct. A paper by 

 Darwin, was presented in March, before the Linnean Society, on the 

 " Action of carbonate of ammonia on the roots of certain plants." In JEJu- 

 phorbia, peplus a cloud of fine granules is formed in the root-cells, even 

 when the carbonate is dissolved 1 part to 10,000 of water. In Cyclamen 

 the roots are turned green by the carbonate. At the same time Darwin 

 also presented a paper on the "Influence of the carbonate of ammonia 

 on chlorophyl bodies." Dr. Emil Detlefsen, in a paper on what Darwin 

 has called the "brain function" of the root, in the Proceedings of the 

 Wirtzburg Laboratory, concludes that the whole of the growing part of 



