156 BOTANICAL GAZETTE [AUGUST 
Citation of a few of the 18 chapter headings will give an idea of the scope 
and perhaps the viewpoint of the work: (i) ‘“‘The various ways in which plants 
appeal to the interests and mind of man”’; (ii) ‘‘The prevalence of green color 
in plants, and the reason why it exists”; (iii) ‘‘The profound effect on the 
structure of plants produced by the need of exposure to light”; (iv) ‘The 
kinds of work that are done by plants, and the source of their power to do it”; 
(xii) “The many remarkable arrangements by which plants secure union of 
the sexes’; (xvii) “‘The remarkable improvement made in plants by man, 
and the way he brings it about.” 
The author pronounces himself a vitalist of a worthy type, ‘perfectly 
natural vitalism based on the superior interpretive power of an hypothesis 
assuming the existence in nature of an X-entity, additional to matter and 
energy, but of the same cosmic rank as they.” This is contrasted with “a 
supernatural vitalism of the theological type.” One wonders whether the 
X-entity as defined above would not satisfy any of our present theologians, 
and whether the distinction is not a matter of words rather than a real differ- 
ence. It should be stated that the X-entity is called in here only to explain 
the mechanics of development and inheritance. As a matter of fact, the safe 
position here is that of the agnostic; for we certainly do not know, in spite of 
assumption and positive statement to the contrary. Nor should we be dis- 
couraged by the fact that we have not made great progress in the physico- 
chemical explanation of development and inheritance, for the fundamental 
physics and chemistry of the material here involved are little developed. The 
serious study of the chemistry of proteins has nearly all been within the last 
two decades, and that of the physics of colloids withina decade. Every treatise 
on these subjects points out much more that is unknown than is known. The 
strides we are making in these fields, along with a phase of work that is now 
only beginning, namely, application of the methods of protein and colloidal 
physics and chemistry to-the study of protoplasm, promise great progress in 
the immediate future. Here also we should not lose sight of the great contri- 
bution of KLess and other experimental morphologists. These are the days 
of hopeful agnosticism in physiology. 
One is disappointed at the overworking of adaptation in the book. An 
adaptational explanation is apparently placed coordinate with the physical or 
chemical explanation. This may make the book attractive to laymen, but it 
_ hardly expresses the present spirit of plant physiology. The book also con- 
tains many statements not abreast of our present knowledge. The following 
sentence savors of INGENHOUss’ original statement: ‘It vitiates the air by its 
respiration, but in the long run purifies it still more by its photosynthesis.” 
I believe it is now fully proved that vitiated air does not result from increased 
carbon dioxide content. Alcoholic fermentation of the yeast is spoken of as 
Siving a copious release of energy available for growth. Also the yeast is said 
to be unable to respire in any other way. Per weight of sugar used, alcoholic 
fermentation releases about one-twentieth the energy released by aerobic 
