1897.] Recent Literature. 14f 
motive of the collection is the emphasis which is placed upon unlike- 
nesses and their survival because they are unlike. The author also 
denies the common assumption that organic matter was originally en- 
dowed with the power of reproducing all its corporeal attributes, or 
that, in the constitution of things, like produces like. He conceives 
that heredity is an acquired force, and that, normally or originally, 
unlike produces unlike.” The author's a priori reasons for belief in 
the hypothesis of evolution are “the two facts that there must be a 
struggle for existence from the mere mathematics of propagation, and 
that there have been mighty changes in the physical character of the 
earth, which argue that organisms must either have changed or per- 
ished.” On the other hand, “the chief demonstrative reason for be- 
lief in evolution is the fact that plants and animals can be and are 
modified profoundly by the care of man.” 
The body of the book is in three “ parts,” the first including essays. 
touching the general fact and philosophy of evolution ; the second, 
those expounding the fact and causes of variation ; and third, those 
tracing the evolution of particular types of plants. The first essay 
gives name to the book. In it the author discusses (1) the nature of 
the divergences of plants and animals, suggesting the Mycetozoa as the 
point of divergence; (2) the origin of differences, holding that all 
plants and animals came from one original life-plasma which had the 
power of perpetuating its physiological but not its structural identity, 
no two organisms ever being exactly alike, it follows that unlike pro- 
duces unlike; (3) the survival of the unlike, this being an extension 
of our notion of the meaning of the phrase “ the survival of the fittest,” 
by showing that the fittest are unlike. 
The author gives us some interesting pages on the species dogma, in 
which he pointedly shows the inconsistency of those who demand ex- 
perimental evidence of the evolution of a species, and yet reject “ hor- 
ticultural species” because they have been produced under cultivation. 
Many examples are given of the origination of well marked “ varieties ” 
which are much more different from the species from which they sprung 
than are the recognized species from one another. Here Professor 
Bailey’s experience as a horticulturist enables him to cite striking ex- 
amples of what the candid reader must admit are good species of beans 
(Phaseolus), tomato (Lycopersicum), maize (Zea), soy beans (Glycine), 
ete. The horticulturist who is familiar with the plasticity of plants, 
and who is accustomed to see new and persistent forms arise, cannot 
help being an evolutionist, nor can he help being impatient with the 
botanist who refuses to accept such forms as true varieties or species as 
