1816 Journal of Applied Microscopy 



ger's PracticHtn* In the first edition of the translation the translator added 

 some notes of his own and also some additional figures, but all such matter was 

 clearly indicated by brackets. In the second edition many brackets were removed, 

 and in the last edition all brackets are dispensed with and the translator's notes 

 have been incorporated into the text, so that in reading the book no one can dis- 

 tinguish what rests upon Strasburger's authority from that which has been in- 

 serted by the translator. This is particularly unfortunate, since in all the German 

 editions stress has been laid upon the fact that Prof. Strasburger has drawn all 

 the figures, and that all statements, even when they concern matters of common 

 knowledge, rest upon his own investigations. 



While the fact that the English book has reached a fifth edition indicates 

 that there is a demand for Strasburger's Practicutn in English, we think it would 

 have been far better to have presented a faithful translation with an appendix 

 suggesting English and American types which could be used where the German 

 forms are not available. c. j. c. 



Wettstein. I. R. von. Der gegenwartige Stand A Study of the literature of the origin 

 unserer Kentnisse betreffend die Neubil- of forms shows that during the past 

 dung von Formen im Pflanzenreiche. Ber. ^ i • i i j ^- i ,i 



d. deutsch. hot. Gesell. 18: 184-200,1901. century logical deduction and theor- 

 izing have often been more prominent 

 than direct experiment and observation. Such a study also shows that botanists 

 have contributed comparatively little to the subject. 



Characters of great constancy, which are affected but little or not at all by 

 life conditions, the writer designates as " organic characters " (Nageli's Organi- 

 zationsmerkmale). Another set of characters are designated by the term 

 " adaptive characters." Most family, genus, and many species characters be- 

 long to the first category, but characters of races and individuals are also in- 

 cluded ; many species characters and most race and individual characters belong 

 to the second category. 



Both categories of characters are always to be distinguished in plants, but it 

 is not always easy to decide to which category a given character belongs. Some 

 plants, like Pleris aquilina, have but few adaptive characters and consequently 

 appear about the same in all conditions, while others, like Potentilla, respond so 

 readily to external factors that a great variety of forms is produced. 



The author's summary is, in part, as follows : The degree of organization of 

 a plant is to be referred to inner causes. Organic characters can be changed 

 by the fixing of adaptive characters, by crossing and especially by hcterogeuesis 

 (the sudden appearance of new forms). In the production of adaptive charac- 

 ters external factors are predominant, while crossing and heterogenesis — espec- 

 ially the former — play a subordinate role. This holds for natural conditions ; 

 under domestication, artificial selection exerts an important influence in the pro- 

 duction of new forms, but in nature, selection can have but little and at most an 

 indirect significance, being efficient, as a rule, only in so far as it removes the 

 unfit. c. J. c. 



* Handbook of Practical Botany, for the laboratory and the private student, by Prof. E. 

 Strasburger. Translated and edited from the German with many additional notes by W. Hill- 

 house. 5th Ed. London, Swan & Sonnenschein & Co., 1900. 



