r 



1907] CURRENT LITERATURE 457 



4 



netic, rather than in all directions, or even in only two directions. ''I maintain 

 . . . . that mutation is not a special kind of variability .... but it is a part of 



irenn 



While 



mony with the views of mutationists, small comfort can be obtained on the other 

 hand by Neo-Lamarckians, for there seems to be no evidence in favor of the notion 



that are found to arise in the soma. Even if 



variations 



faucn variations are tirst visible in the soma, they are possible only when the germ 

 plasm has developed a soma capable of variation. The botanists seem to have 

 more generally accepted the theory of mutation than have the zoologists. It 

 scarcely seems possible that one method has been uniformly effective in animal 

 evolution and another as uniformly in plant evolution. Very likely nature has 

 been more multiform in her methods than most of us have yet been willing to 

 believe.— Henry C. Cowles. 



Vegetable physiology 



A new edition of Green's Vegetable physiology has just made its appearance 

 from an American press.^ Unfortunately the author has not written any preface 

 to the new edition and so Tvhat changes he has made can be ascertained only by 

 laborious comparison of the new with the old. The alterations arc more numerous 

 than extensive, and it is evident that in large part the old plates are used. Yet 

 the changes suffice for the incorporation of the more important recent advances 

 in the science. 



One of the most striking improvements is the transfer of the chapter on respi- 

 ration from its former connection with the chapter on the aeration of plants to the 

 chapter on the energy of the plant, so that it follows instead of precedes the dis- 

 cussion of food-making and food-getting, digestion, translocation, and storage. 

 The topic might have received more thorough revision in its text to advantage. 

 Other changes are noticeable in the discussion of the absorption of food materials, 

 the chlorophyll apparatus, photos}m thesis, and in the nomenclature and classifi- 

 cation of proteids. 



Not all of the slips have been eliminated in the revision, but the improvement 

 is obvious in bringing the book more nearly up to date. The most striking defects 

 which caught our attention are the retention of the filter theory of dialysis (at least 

 by inference, for the explanation of osmosis is not ver}' clear) and the statement 

 that etiolin is converted into chlorophyll by the action of light. All the recent 

 evidence is against both of these conceptions. 



Of all parts of the book the chapters on irritability seem to us most in need of 

 thorough reworking, but this has not been done. Perhaps the author was not 

 free to make changes that would involve extensive resetting of tyj^e; as to this 

 he does not take us into his confidence. By and large the book is one of the 



Reyn 



Second edition 



Sto. pp, xx + 459. Phaadclphia: P. Blakiston's Son & Co. igoj. $3-00. 



