444 BOTANICAL GAZETTE [NOVEMBER 
having been abandoned and much new material with numerous figures having 
been added. There is a change of view in regard to leaf arrangement, and 
alternation of generations receives some attention. Naturally the relation 
nificance of juvenile stages are of interest to all botanists, and whether one 
agrees with the author or not, GoEBEL’s account is stimulating and should put 
a needful restraint upon those who would blindly assign every such phenome- 
non to heredity and recapitulation. 
The intimation, in the preface, that botanists have left the older fields of 
morphology needs a word of comment, for there are still some of us who feel 
as much interest in the problems of evolution, heredity, and phylogeny, as 
in seeing ‘‘the wheels go round.” We welcome this book as a wholesome check. 
The morphologist whose principal interest is in phylogeny needs it, just as the 
experimental morphologist, whose principal interest is in something other than 
phylogeny, needs to know more about the structure and development of the 
objects upon which he is experimenting. 
The second volume, dealing with special organography and containing the 
index, will be awaited with interest CHARLES J. CHAMBERLAIN. 
NOTES FOR STUDENTS 
Osmotic pressures—RENNER3 has rendered a very important service to 
plant physiology by summarizing and subjecting to a critical analysis the 
literature of recent years dealing with the methods of calculating the osmotic 
22.4 atmospheres for undissociated salts. The discussion centers about the 
work of Morse, Frazer, and their co-workers, whose exact determinations 
have now shown clearly that such solutions must be made up in weight normal 
instead of volume normal concentrations in order to yield osmotic pressures 
agreeing with the gas laws. RENNER shows from calculations based upon the 
determinations of Morse that there is a very close relation between depression 
of the freezing point and osmotic pressure. He claims indeed that all the dis- 
agreements in the literature between the results of the cryoscopic and plas- 
molytic determinations of osmotic pressure are traceable to the fact that the 

RENNER, O., Uber die Berechnung des osmotischen Druckes. Biol. Centralbl. 
32:486-504. 1912. 
